There are tons of map mashups on the web, but most of them are not very touchscreen friendly.
This site i just found.
is very cool, and somewhat touchscreen friendly but not totally. But has a lot of cool **** going on including gps tracking (havnt tried that part out yet).
But anyway, i know there has to be some good web coders on this forum somewhere that could whip up a mashup that was touchscreen friendly and had carputer based features like traffic, gas, ects all in one interface. There are multiple solutions for all of these things but nothing thats carputer based and integrated.
This may be the closest thing to it.