This site has some good things to think about while shopping for used bike
http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.clarity.net%2F~adam%2Fbuying-bike.html&ei=6pHySIG8C4nOsAP_oq3-Aw&usg=AFQjCNGz8tCLbxISG1TIZdGO6sBUDINuHw&sig2=1vkyEHfSrE4zvsZeXHNmfw (http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.clarity.net%2F~adam%2Fbuying-bike.html&ei=6pHySIG8C4nOsAP_oq3-Aw&usg=AFQjCNGz8tCLbxISG1TIZdGO6sBUDINuHw&sig2=1vkyEHfSrE4zvsZeXHNmfw)