I bought a Dell Axim X-50 pocket computer with all the bells and whistles for around $150. It was like new in the box and came with the GPS option and all of the supporting software. . I also bought the Night force software from Bill Shehane. I haven't used the gps around here, but if a guy were to take it hunting in unfamiliar territory it could be of some use. I also have a Kestrel 3500, but I don't know if I trust the elevation #'s it is spitting out at me. Using the elevation from the GPS along with inputting all of the info from the Kestrel into the Night force program on the pocket PC takes the guesswork out of most of the long range shooting. The only problem with all of those electronics is the cold temps....things tend to shut down!!!
Good luck