Since lots of people, had difficulties with cygwin, in7ane, has come up with a nice gui PC tool for generating the maps...It's still in development phase (as most of this project :-), so if you find a bug, please report it in this thread...
it does require Microsoft .net 2 from http://www.microsoft.com/downloads/ (~22Mb)
but installation and usage seem to be much easier and straight forward for average user :-)
[EDIT] Here is a link to a newer version, featuring:
- custom map creation
- GPSFS - map compression format...
- POI/directions support
- numerous map vendor support
- hybrid maps and more http://www.in7ane.com/psp/gmdl.html
Check the thread for details and latest versions...