Some time ago I bought shareware GPS mapping program GPSDash (see
GPSDash 4 PocketPC).
The relevance is that it offers a map geo-calibration and tiling program that runs on the PC; the tiles are then copied to PPC for display.
Unfortunately I find a number of its moving-map features annoying although it is generally a very polished program. It also appears to be stagnant with no new releases for several years.
But you might find it interesting to download, play with and plagiarise!
Mike.