there's already good books on navigation - I usually recommend Wilderness Navigation, by Bob and Mike Burns, it's quite good as it is easy to understand for the novice, very straightforward and laid out well with great illustrations.

And if people turn straight to the chapter on the GPS there is a big box that says "if you skipped all the other chapters and turned to this one first, thinking that using the global positioning system will make it unnecessary for you to learn map and compass, please go back to the beginning of the book and read at least chapters one through five before reading this chapter. Using GPS technology effectively requires a basic understanding of how to read maps and how to use a compass."

SAR teams everywhere should write these guys thank you letters.

For an online resource, I usually point people at http://www.princeton.edu/~oa/manual/mapcompass.shtml - it's not as thorough as the book but does okay for map and compass basics.