There is a new source for maps for Mapsource,     (You need to Login or Register

I downloaded there maps for Maine and they work great in my Mapsource.  I have not yet tried downloading them into my GPS, though.

This first requires you to have Mapsource.  Mapsource comes with any Garmin map data you buy.  I do not know if you can get mapsource without any map data.  I keep downloading updates free, so it could be the software itself is free, just the data costs money.  If so, you could use mapsource with the free gpsfiledepot data for free.