Is there one?
Is there a reason you want to turn the GPS off? Unless there is an application actively using the GPS, it uses a neglible amount of power.
Samsung Galaxy Nexus
AOKP Rom - current build
cool, will have to try it. I use the car mount mostly for listening to music as opposed to GPS (I usually know how to get where i want to go) and the GPS auto launching is very annoying to me.