I found a way to get mapsource for free, legally.

First install the trainings center software.
http://www8.garmin.com/support/collection.jsp?product=999-99999-04

this installa a basemap in the mapsource directory, now that the
directory is there install the mapsource update.
http://www8.garmin.com/support/download_details.jsp?id=209

You only get a pc basemap, but you can use custom maps now to get more
detail.