Terrorists!
We buy GPS modules for our surveying systems, one of the requirements on the export licence is that they are not allowed to be programmed to follow a pre-determined course.
Now the italians have discovered the technology for navigating a model aircraft we are no longer safe.
sigh If only I could get some real clock speeds on hardware like this. These are what, 16 MHz?
It seems to me that 16 MHz is plenty for waypoint following and attitude control but if you really need more processing power you could try http://www.gumstix.com/