Alan Cooper's List: http://www.cooper.com/alan/homonym_list.html
100 Homonyms: http://homeworktips.about.com/od/englishhomework/a/homonyms.htm
A to Z List: http://www.zyvra.org/lafarr/hom.htm
Commonly Misused Words and Phrases: http://wsuonline.weber.edu/wrh/words.htm
Self Study Site: http://a4esl.org/q/h/homonyms.html
Readquarium: http://gamequarium.org/readquarium/homophones.html
Fun Brain Game: http://www.funbrain.com/whichword/index.html
Homonyms: http://editingandwritingservices.com/homonym-heaven/