A word on exporting TrackWaypoint layers as GPSMapper files.
(NOTE: You should always save your data as a gpspoint or Viking file also because Viking cannot open gpsmapper files)
The comment field for each track/waypoint you want to export to GPSMapper should be in the following format:

Name RGN## 0x####
   - or -
Name RGN## 0x##

Where the first '##' is 10, 20, 40, or 80, and the second group of '#'s is the type of region.
See the GPSmapper ( http://gps.chrisb.org/ ) docs for more details.
By the way, if anyone knows of an open-source program to make compiled maps for (preferably Garmin, 
but I would appreciate info on other brand) GPS receivers, please tell me!