I use GPS TrackMaker on a regular basis for loading waypoints to my Rhino GPS. It works great and best of all it was a freebie. It has the ability to read shapefiles and offers various interfaces for a host of GPS devices.
This product rates a 10 out of 10 in my books and you can look forward to a complete review of the utility in the GPS Section of ForestPal.com
To get TrackMaker please visit http://www.gpstm.com/index.php.