I use my cell phone as my primary phone. I use an incredible about of minutes every month, minutes that I sometimes don't anticipate using, don't realize I've used, and consequently get very angry I have to pay for.
WatchMyCell is designed to keep a watchful eye over your cell phone account for you. The site launched today and offers you a free download of a program which will check your cell phone minutes every 3 hours, when you're close to hitting your limit the program will alert you via text message or email.
With a reference to Cornell on their blog, WatchMyCell seems to be the brain child of a few college students (which is pretty obvious reading their site). They claim that no personal information about you or your cell will be stored on their server, and all information sent to your cell phone provider is sent over 1024 bit encryption.
WatchMyCell requires a Windows PC connected to the Internet and current only supports Cingular, Sprint/Nextel, and Verizon phones.