There are several different types of GPS that can have topo maps for example all i had to do was plug the GPS into a computer and download it and I have heard that others just have it built in on their programs

I purchased a medium priced GPS then downloaded the program rudy mentioned above. Works great and has great detail.

I've checked out a couple of dedicated GPS websites and several of the "experts" rank the DeLorme DN40 (I think that's the model, it's the orange one) as the best practical model. The nifty cool (but still all-around good) model is the Oregon 550 (once again I think that the model offhand). The 550 has a bigger screen and is touch screen. The PN40 is faster, tougher and has areal photo capabilities.