Here is a good site: http://www.gpsvisualizer.com/. Check out the Links section.
If you have a GPS-enabled cell phone it might get you much of the functionality you would get from a dedicated (and expsnsive) GPS unit. Your phone's features limit what kind of software you can run on it, but apparently (and I'm just starting to look into this) touch-screen PDAs like the AT&T Tilt can run Delorme software and let you carry topo maps in your phone on which you can overlay your position, load waypoints from your laptop, etc.
My Treo 650 which is not GPS-enabled has aftermarket Bluetooth units available for it, though the extra cost would almost buy me a newer PDA.
If anyone here uses a cell phone / PDA as a GPS unit, please share your experience!