Re: Garmin and POI.
Don't knoiw anything about Map Source but in this post -

http://www.themodernantiquarian.com/forum/?thread=42488&message=530416&offset=325

there's a link to a post on Fourwinds' site about using a different piece of software to get a kml file into your Garmin, should work with the TMA database too.

-Chris