Englishclub.com  http://www.englishclub.com
Catering to a worldwide ESL community, the site is user-friendly and filled with comprehensive and tangible resources for students and teachers alike.  Students will find clear information on English grammar, vocabulary, pronunciation, and the four basic skills.  Teachers will find a treasure load of classroom activities, lesson plans, and handouts.

English @ home  http://www.english-at-home.com/
This site is helpful for those who want to teach themselves English.  It contains grammar, tense and verbs, pronunciation, vocabulary, idioms, and tests.  It also has special activities and strategies for learning English, such as games and listening to live English radio stations.

The Blue Book of Grammar and Punctuation  http://www.grammarbook.com/
This site is a good reference site for English grammar and mechanics.  Besides clear explanations, there are sections for users to practice and test their usage.

Dave's ESL Café  http://www.eslcafe.com/index.html
No list of ESL sites would be complete without this one known the world over.  It features vocabulary lists, quizzes, chat rooms, and more for both teacher and student.

Learning English  http://www.bbc.co.uk/worldservice/learningenglish/index.shtml
Student-oriented, this site is part of BBC World Service, and uses radio, magazines, and cassettes to teach English.  It also offers multilingual services so that Chinese learners can log on to BBC Chinese.Com and enter Learning English to get materials especially tailored to Chinese speakers.  It is also a good resource for teachers.

Iteslj.org  http://iteslj.org/links/
Maintained by the Internet TESL Journal, this site is a giant database divided into two categories: one for students and the other for teachers.  Within each category, there is a list of subdivisions that cover almost anything one wants to know.  A search engine is attached so that users can do an all-word or keyword search.

The Educator's Reference Desk  http:www.eduref.org/
A Web-based service founded by the U.S. Department of Education, this site provides information on various subjects.  The component AskERIC Lesson Plans Collection contains over 200 lesson plans.

The LinguaCenter Grammar Safari  http://www.iei.uiuc.edu/web.pages/grammarsafari.html
This site directs the user to look for real-world examples of grammar on the Web and encourages them to compare the informal English they find to the formal English and grammar they learn in the classroom.

Virtual Language Center  http://vlc.polyu.edu.hk/
This is a resource-rich learning site integrating multimedia and an online dictionary for students and teachers.  It includes activities in such areas as grammar, reading, idiom, and listening, each of which is linked to the VLC dictionary.   

Adult Education ESL Teacher's Guide  http://humanities.byu.edu/elc/teacher/teacherguidemain
This site is designed for adult students but can be adapted for secondary school students.  Materials and worksheets are provided with lessons for beginning, intermediate, and non-literate students.  Each lesson is accompanied by teacher training modules.

Conversation Questions for the ESL/EFL Classroom  http://iteslj.org/questions/
Good for teachers and those working with ESL students, this site is a project of the Internet TESL Journal and covers a wide range of topics with questions that can be used in conversation groups or as journal assignments.

Karin's ESL Party Land  http://www.eslpartyland.com
This site provides teachers with lessons and materials to use in class.  It has over 50 interactive quizzes for students, 15 discussion forums, and additional links.

ESLgold.com  http://www.eslgold.com
This site contains resources and materials for both teachers and students. 

Aardvark's English Forum  http://www.english-forum.com/00/interactive/
This site is for both teachers and students.  It has advertisements on it, but it has good links to other sites of interest, good materials for self-instruction, and material for downloading.

Purdue University's Online Writing Lab  http://owl.english.purdue.edu/
This is an excellent site for students and teachers alike.

English Second Language Resources  http://www.rong-chang.com/
This site is for teachers and students alike.  It is regularly updated and its own good material plus links to other good ESL sites offering free material.

TOEFL OnLine  http://www.gettoefl.com/
Although this site requires fees for some of its courses, other materials and information are free on the site and it answers virtually every question you can think of pertaining to TOEFL.

Sussex University's Virtual CALL Library  http://www.sussex.ac.uk/languages/1-6-6.html
Good for students and teachers, this site is point of access to the diverse collection of Computer Assisted Language Learning (CALL) software available on the Internet for downloading.

Grammar Bytes  http://www.chompchomp.com/
This is an interactive site for both students and teachers alike.

About Grammar  http://esl.about.com/blgrammar.htm
Although this site has annoying advertisements and certain materials require fees, it is still good for its resources and list of topics.