Randall's ESL Cyber Listening Lab
Great exercises for all levels: http://www.esl-lab.com/index.htm
English, Baby! - slang
conversation and pop music lyrics http://www.englishbaby.com/
Takako's Great
Adventure - a thematic set of lessons that uses Shockwave
The English Listening Lounge - listening activities that uses Real Player
http://www.englishlistening.com/
Mouth Manglers - tongue twisters
http://www.elfs.com/MMz.html