If you guys want some free topo maps that will load into MapSource check these out:
I've got two loaded that seem pretty nice:
Arkansas Topo 24k+
Arkansas Contour 20ft Overlay
After installing you will see a pulldown in MapSource where you can change maps. Kind of nice to see what the topos look like for all of these GPXs.
I think the overlay can be used on a gps in conjunction with a base street map. That way the topo will be overlaid. The first one, the Arkansas Topo 24k+, is nice in MapSource, but when I used it on my Nuvi at SLAP last year it was too much information unless I really zoomed in.
Anyway, I thought I'd throw this out there since it's a pretty cool freebie.