I supply a map rendering and route-finding library called CartoType. I've now written a tool to convert OSM data to CartoType's native data format, which is very compact (the whole of Greater London fits in 6MB). This means that using map viewing programs that I shall put up on the CartoType web site (www.cartotype.com) anybody will be able to use OSM-derived maps on Windows Mobile devices without the need to be on line to the OSM server.

CartoType runs on ordinary Windows (XP etc.) Windows Mobile, Symbian OS and Palm OS.