• ESL + Computers
• Language Guide Wow!
• Activities for English Students  lots and lots, all different skills
• English Club  lots of resources (mostly British English)
• About.com: English as a Second Language, A website with many different parts.    Look down the left side and column for links to topics, such as Vocabulary, Listening Skills, Writing skills, Grammar, and many more.  (Try to ignore all the ads.)
• English, Baby

To practice listening:

• Randall's ESL Cyber Listening Lab
• Everyday English in Conversation 
• Voice of America news
• Voice of America special English
• NPR, National Public Radio
• KWMU St. Louis, public radio

To learn new words:

• Cambridge Dictionary of American English good ESL dictionary
• Longman Online Dictionary  another good ESL dictionary
• Merriam-Webster  click on the speaker symbol to hear pronunciation of words
• Idiom Connection
• Internet Picture Dictionary

Enjoy reading:

• Topics An Online Magazine for Learners of English
• Newspapers, from all over the world
• More newspapers 
• Awesome Stories, good reading
• Takako's Great Adventure

• Tower of English
• Free English
• Purdue's OWL: ESL Resources
• Internet English Resources, from the University of Illinois' Intensive English Program.  Lots of great resources here for online learning and enjoyment. 

• Translation dictionaries from IPL
• English, Baby
• TOEFL Online
• Dave's ESL Café
• English Learner Movie Guide