The SpeedTrap Exchange is a good resource if you are looking to avoid traffic tickets. You can find known speed traps in your area or in any other area you care to look around in. You can also add the speed traps you know about to help others avoid getting traffic tickets.

I could imagine a cool mashup where someone integrates this data with Google Maps so you can automatically find speed traps on your route when you are driving. Someone get on that please! ;)