In a nutshell buy the book: Outdoor Navigation with GPS. This is a great book that explains how to use any GPS unit . There are many misconceptions that the author (Stephen W. Hinch) clears up. You can buy the book at Amazon for $11.53. (Copyright 2007)
I just bought the Delorme PN-20, a very powerful GPS. Members can look forward to enhanced topo maps, track logs, and additional information to help navigate hikes.
I just published the hike: Calico Tank and Peak via the East Route. Dave and Richard found the route and it's one of the best short scrambling routes in Red Rock. It's the perfect winter hike!