Escuelas Oficiales de Idiomas - The site for all the students learning a language in our schools. You'll find chats, links for students, noticeboards etc.
My agony aunt webquest - This webquest is a cooperative project where students are exposed to authentic material in order to write request and advice letters.
Dave Sperling's ESL Cafe - The site for learners and teachers of English as a Foreign Language.
The Internet TESL Journal - Activities for students and teachers (self-study quizzes, crossword puzzles, treasure hunts, etc.) and more.
Guide to Grammar and Writing - This site has a lot of language work at the sentence, paragraph and text level. There are complete grammar explanations and interactive exercises and quizzes which evaluate your understanding of the language.
Soon On-line Magazine - A grab bag of different articles and stories which aren't too difficult for low intermediate students.
E L Easton - Excellent source of links to all kinds of materials - self-study materials for students and more.
ELT Spectrum - The Oxford English Dictionary's magazine where you can find articles, worksheets and free on-line dictionary.
Learning English with the BBC - Articles, quizzes, listenings and more.