• The Online English Grammar
• The Grammar Safari
• Grammar Quizzes
• CNN Newsroom and Worldview Grammar Exercises
• Grammar Zone from English-Zone.com
• English Grammar Site with lots of links to grammar related things, by Rong-Chang Li

Vocabulary

• Cobuild Idiom of the Day
• Vocabulary Quizzes
• CNN Newsroom and Worldview Vocabulary Exercises
• The Monthly Idiom (Comenius)
• Vocabulary Zone from English-Zone.com

Reading

• BBC News
• MSNBC Cover
• USA TODAY
• CNN
• Internet Public Library
• Reading Zone from Emglish-Zone.com
• Reading List of reading resources, by Rong-Chang Li

Writing

• The Communication Station
• Online Writing Lab
• Writing Help
• Writing Zone from English-Zone.com
• Writing List of writing resources, by Rong-Chang Li

Speaking

• English Pronunciation (Okanagan University College)
• Pronunciation  List of pronunciation resources, by Rong-Chang Li

Listening

• Easton Language Education
• The English Listening Lounge
• Randall's ESL Cyber Listening Lab
• Listening Quizzes
• BBC World Service
• Language Box - World News Radio
• Watch Film
• ABC News
• Interactive Listening Comprehension Practice (Lingua Center)
• Listening List of listening resources, by Rong-Chang Li

Dictionaries

• Cambridge Dictionaries Online
• Hypertext Webster Gateway
• Encyclopaedia Britannica
• Ultra Lingua's Web Dictionary
• On line Dictionaries Links to many on line dictionaries, by Rong-Chang Li
• Encarta World English Dictionary

Games and quizzes

• ESL quiz center
• Activities for ESL students
• EnglishClub fun
• English Quizzes by Kitao & Kitao
• ESL Quiz Center by Dave Sperling
• English Exercises and Quizzes
• ESL Games

Software

• Creative Technology (Software for Teaching and Learning)
• Half-Baked Software (Create your own activities with Hot Potatoes)
• La Güebera (Create your own activities with Güeb) 
• Marmo's Javasript Templates (Use free JavaScript templates for your activities)

Song lyrics

• Songfile
• International Lyrics Server
• Risa Song Lyrics Archive

For teachers

• Writing Resources for Teachers
• The Teacher's Desk (Lesson Plans)
• Teacher Talk Home Page
• Teacher's Zone form English-Zone.com
• Sites for teachers
• Lesson Plans and Class Activities

Miscellaneous

• Biographies (25.000 personalities)
• Film transcripts
• GuardianUnlimited Quizroom (Test your culture)
• ESL Chat Central by Dave Sperling  (Chat only in English)