Beware of Mobile Sidewalk!
Beware of theses guys at "Mobile sidewalk":http://www.mobilesidewalk.com/ a buddy of mine, Brian, told me about them, I browsed their site and then they asked me for my mobile number. Little did I realize that they would start charging me $10/month via T-mobile for a service I never used.
Amazing that folks can get away with this kind of stuff since it is at the bottom of a bill that you'd never notice. T-mobile is super (unlike Cingular, arrgh, those guys are just terrible, I'm still fighting over bills for the last three months) in blocking them, so if you head to this site, don't give them anything!