First off, one important thing to remember is that there is a difference between the old EU member states (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, Sweden, and the United Kingdom) and the new EU member states (Bulgaria, Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Romania, Slovakia, Slovenia).

If you have a passport from the new EU, you aren't eligible to work in the old EU right away. It depends on what country your passport is from and where you want to work. Different countries are allowing different new EU nationals to work in their countries. Please see the official EU expansion website. Laws about work visas change often, so be sure to check with the embassy of the country you want to work in as well.

Some people will say it's possible to work in the EU without an EU passport, others say it's impossible. The fact is that it IS possible to find legal work in the "old EU", but it is rare. Basically, if you can prove that you're qualified to do a job than a national can't, then you may be eligible for a visa. There are going to be many many English speakers in EU, even in non-English speaking countries. The key to getting a work visa is having qualifications that a national doesn't have. Read these recent discussions to find out more: The EU for Americans, Getting a Job Without an EU Passport, North American Teaching in Europe. One important thing to remember is that the UK and Ireland are part of the EU, so if you have a passport from either of those countries, you are eligibile to legally work in the EU.

Schengen Countries
The 15 Schengen countries are: Austria, Belgium, Denmark, Finland, France, Germany, Iceland, Italy, Greece, Luxembourg, Netherlands, Norway, Portugal, Spain and Sweden. All these countries except Norway and Iceland are European Union members. According to the Schengen Agreement, if you're not from an EU country, or one with an agreement (such as Switzerland) or don't have a resident visa you can only stay 90 days out of 180 in the Schengen Countries, making working illegally and border hopping out of the question.

Overstaying, living or working without a visa, could result in fines, arrest, deportation and/or being banned from entering Schengen countries in the future. You can find information more information in Free Travel in Schengen Countries.

More Countries to Join the EU
Croatia, the Former Yugoslav Republic of Macedonia, Turkey, Albania, Bosnia and Herzegovina, Montenegro, and Serbia (Kosovo) are all trying to join the EU as well. If you are in one of these countries now, you should try to get permission to become a permanent resident. By doing so, you might help yourself in the long run. Not only will you be able to stay legally in the country when it becomes part of the EU, but you will might be eligible for a passport, thus allowing you to work anywhere in the EU.

Keep in mind that things don't happen overnight. It may take up to 10 years after joining the EU for citizens from Croatia, the Former Yugoslav Republic of Macedonia, Turkey, Albania, Bosnia and Herzegovina, Montenegro, and Serbia (Kosovo) to be able to work in the other EU countries. Please see the official EU expansion website for examples of what's happening with the "new EU" countries.

Non-EU European countries
Iceland, Liechtenstein, Norway, and Switzerland have all elected not to be part of the EU. However, some countries have agreement allowing their nationals to work in EU member states. If you have a passport from one of these countries, you may be eligible to work in the EU. Check with your embassy for more information.

EU Passports
The EU keeps expanding and with its expansion it's getting harder and harder for those without an EU passport to work there. So what is an EU passport? It's a passport from a country in the EU. In order to get a passport from an EU country, you have to have citizenship. Citizenship is the only way to get it. You can't buy one or fill out a special application for one.

If you don't have a passport from any EU country, try to see if you qualify through ancestory, birth, marriage, or residency. Just remember to look over the information carefully, as some countries may ask you to give up your orginal citizenship.

For ancestory, citizenship is usually passed down by your mom or dad, though someplaces, like Italy may go back to your grandparents. You'll have to check with the embassies for more information. In general, you can usually only claim citizenship through ancestory through your parents, sometimes you can claim it through your grandparents. Italy is fairly straightforward and easy to gain citizenship if you can prove ancestory, for example.

If you were born in an EU country, then you might also qualify.

Through marriage and time spent in that country, you may get citizenship.

If you already legally live in an EU country and have residency, try to find out the details about gaining citizenship through the immigration office.

Residency
Another way to work legally in the EU is through residency. Some countries let people on student visas work for a limited number of hours. Likewise if you are married to an EU citizen, you will probably be able to get residency and legally work in that country.

Same goes for birth and possibily ancestory, but again, you'll have to check with the embassy. Also remember that just because you are entitled to work in one country doesn't mean that you can work in all of them. Check with immigrations for specific rules.

Work Visas
In order to get a work visa, you usually have to prove that you can do a job that no EU national can do. Teaching English sometimes allows you to get a work visa, though usually not in the "old EU". Remember that there are many English speakers in the EU, so the more qualifications and experience that you have, the better.

If that doesn't work, there are other options, such as Working Holiday Visas. If you qualify you can get a legal work visa for a specific amount of time.

For teachers, you might be able to work at an international school. There's lots of competition though. You'll have to be highly qualified which means that you'll have to have at least 2 years teaching experience and a teaching license. These are the basic requirements, you'll have to a lot more if you want to teach in an international school. And even if you do have lots of experience and qualifications, schools would much rather hire someone from the EU than someone not from the EU. Still, if you think that you might qualify, try looking at this article about international schools to find out how to apply.

Language institutes might be willing to sponsor a visa for you. Though this rarely happens in the "old EU", countries in the "new EU" might be willing to help you. You can find jobs in TEFL.com, Euro Jobs, and Dave's ESL Cafe. Summer and Winter Camps are always in need of native speakers. Some of them will get you a visa or help you with the process.

Good au pairs are always needed. AIFS, IAPA, Transitions Abroad Au Pair, Transitions Abroad Au Pair in Europe are good places to start research.

Country Specific Institutes
The following have been known to help with visas in the past. Try contacting them if you would like to work in Europe.
Czech Republic: The Boland School,
Italy: ACLE,
Spain: English Unlimited
Russia: Language Link, AAFL,
Various: Saxoncourt, SOL, IH, Bell, ILS,

Placement Agencies
Places like CIEE, World Teach, I-to-I all offer help with visas and a job for a fee. You can find more placement agencies in Working Holiday Visas. If you decide to go with a placement agency, keep in mind that most English teaching jobs only pay about 500 to 1000 USD a month. Housing and heating costs are often high in other countries, so be sure to balance the placement fee against the money that you'll make. Remember to ask your placement agency if they can get you a legal work visa to work in the EU. Agencies cannot get a visa for a country that doesn't accept non-EU citizens.

Volunteering
Many long term volunteer agencies with provide you with a visa as well as a stipend. Get out the following: Peace Corps, VSO, and CUSO.

More information
Transition Abroad has articles about Teaching in Western Europe and Teaching in Europe, they might be helpful to find out more about visas and jobs. UWEC has a list of some jobs.

TEFL Courses That Get You Jobs
Some TEFL courses will let you work in their institute after you sucessfully pass their TEFL course. Canterbury in Spain is one of them. Here are some discussions about them. Canterbury 1, Canterbury 2, Canterbury 3. The Caledonian School in the Czech Republic is another. If you do decide to do a TEFL course with a company that lets you work in their institute, be sure to ask about visas.

Sharon de Hinojosa (naturegirl321) has lived and worked in the US, Scotland, Spain, the Czech Republic, China, Korea, and Peru. As well as teaching short-term in Venezuela and Taiwan.

She has created TEFL Tips which has information for teachers from writing a CV, to giving a demo lesson, learning the local language, teaching tips for the classroom and more.

Since living in Peru since August 2004, she wrote The Ultimate Peru List http://www.theultimateperulist.blogspot.com/. With 80 pages it's a comprehensive guide for those living in or moving to Peru.