Advice for new teachers
A number of TEFL Qualifications are available, albeit at some cost, but obtaining one is highly recommended. Most schools will probably want you to have an existing university degree in some subject, but if you don't have one of these you still might find a place although it will probably entail more looking. If you want to get some idea of the sort of things you will have to learn then TEFL Boot Camp will probably be of interest.
Take care when choosing your school if you are thinking of obtaining a certificate abroad as there are a number of unscrupulous operators. 
Moving to another country
Many people may wish to move to another country to work - indeed, this may be their primary motive. Justlanded provides a wealth of information which will be invaluable to new residents.
For those wanting to get a feel for the life of an English teacher, Thepaininspain is an amusing and informative blog.
Some information about specific schools may be found at the Teflblacklist.
Although countries vary, it really is best to avoid working illegally. On the other hand, it is very difficult to get employment in European Union countries unless you are prepared to be taken advantage of by cowboy outfits.
See main article culture shock.
Although moving to and living in a new country may seem like an adventure at first, most expatriates suffer some level of culture shock at some point. The best way to mitigate its effects is to understand what it is and how it progresses.
Other useful sites
Clearly you should also take a look at Dave's ESL Cafe - the granddaddy of them all along with its associated job discussion forum; and also sign up for the free TEFL newspaper at English language gazette.
If you want something quick and easy for a class then our article on conversation questions for TEFL classes has some good advice and links.
Once you have new students you will want to know their level. There are some on-line placement tests which claim to b able to help you with this.
Working for a school or freelance
Working for a school and working freelance have different advantages and disadvantages as our School v freelance article discusses; however schools are often the best place for new teachers to start as that article points out.
Before you start working for a school, have a look at our article on cowboy outfits.
Salaries depend on many variables but this link will give you a very broad picture for various countries.
Creating your own classes
If you feel really adventurous then you could follow our guidelines about creating your own topical class.
Other ways of teaching
There are more ways of teaching students than in a classroom. Our article other ways of teaching talks about these.
A selection of links which give advice to prospective TEFL teachers.