Free GPS maps

http://www.gpsfiledepot.com has a pretty extensive selection of free maps. I have loaded them on my old Garmin Etrex Legend CX. I wonder if they would be able to be loaded on the GC somehow. I am going to try the conversion soon. I don't use the map on GC anyway because it doesn't give turn by turn so it's really just a reference - but I have my iPhone 4 so I generally have full mapping and satellite capabilities on that if I need a visual. The GC gets me to the GZ once I'm already in the vicinity.