There are thousands of websites out there which can help TEFL teachers. Here are some you may find useful
Teaching English Website A website set up by the British Council and the BBC. Some useful ideas for new teachers.
Typical errors made by 15 different language groups. Here is an excellent overview of the most common errors made by particular language groups. A great resource if you are heading to a country you have not been to before. It is part of the excellent Language Project website.
Bad ideas in TEFL. Someone's perceptive view of some of the bullshit in TEFL.
Young Learners Some useful information is provided by Language Link (their website contains a lot of common sense).
Sue Swift's blog Lots of good teaching ideas written in plain English.
Developing teachers A website with easy-to-use lesson plans. Have a look at this one!
Stephen Krashen's website Includes the opportunity to download (for free) his excellent book, Second Language Acquisition and Second Language Learning which he wrote in 1981.
TPR World James Asher's website - all about TPR - Total Physical Response. Interesting that he looks younger on his website that he does in the Horizon video made in the 1980s.
Humanising Language Teaching Mario Rinvolucri of Pilgrims runs this website. There are interesting ideas - though you don't have to take them all seriously. Have a look at this article on choice theory for teachers. Interesting stuff.
Perlingua Here you can download some fun games for your students. Word Order is particularly fun.
Macmillan publishing has a website for TEFL teachers. They use it to plug their material but there are lot of good ideas there - in their plugged material as well.
MES English has a website full of free material aimed at young learners.