http://www.literacycenter.net/play_learn/index.php/ - This site is great for reading, listening, and speaking. It has great activities for preschoolers and kindergarteners!!
http://www.brainpopesl.com - This website provides interactive videos, lesson plans, activities and games. It's a great educational resource for teachers, parents and students.Also, the students can practice reading, writing, listening, grammar, vocabulary and pronunciation.
http://www.manythings.org/ - Description from the website: "Web Site Description: A Place to Study English.This web site is for people studying English as a Second Language (ESL) or English as a Foreign Language (EFL). There are quizzes, word games, word puzzles, proverbs, slang expressions, anagrams, a random-sentence generator and other computer assisted language learning activities. Even though the primary focus is for ESL, native English speakers may also find some interesting things on this site. This site is non-commercial and has no advertising."