The Trapster app on my iPhone does precisely that. There's one large blue button at the bottom of the home/map screen labeled "Report". Tap it and your GPS coordinates are transmitted via cellular link and the network gets upgraded in pretty close to real time. Other motorists using the app will get a push notification of the speed trap, if they are within their selected radius of the new threat (phones must be set to accept push notifications or this isn't as immediate). Even if the phone is in your pocket, it'll still sound the warning chime.
I'm sure there's a bit of a lag based on the 3g network's activity, but overall it's pretty slick. It has saved my bacon more than once, and the fact that the revenue collection officers hate it just makes me all the more fond of it.
Huh.
I guess I should break down and read the instructions....;D
Well I’ll be dipped.
There’s the button and a whole bunch of other stuff on the side that I never noticed.
Thanks, man.
:)