Trapster is a free service and client for avoiding speed traps for iPhone, BlackBerry and java enabled phones. Another great thing about Trapster is that it’s community driven: anyone can report speed traps so the maps are updated all the time.

Trapster combines technologies such as GPS and wireless location, voice transcription, geocoding, reverse geocoding, and SMS, with a central database server. It communicates in real time, using the Internet. Since the traps are often moved from one position to another it is vital to get real time information about their location. You can set notifications up on your Garmin or other navigation device if you don’t want to check your phone while driving.