Translating NAV Companion waypoints to another format is as easy
as with any other format.  Just find the Companion_Waypoints database
in your palm backup directory and use it as the input file. 

When translating waypoints back to NAV Companion, though, you need 
to jump through some hoops:  

First, you must merge any waypoints that already exist in the database 
in your Palm Backup directory with the ones you are adding; failure to 
do so will result in only the new points being available in NAV Companion, 
even if you give the new database a different name (it will overwrite 
the old database, even in your backup directory.  That's a feature of 
PalmOS, not of NAV Companion.)  

To merge the databases, use a command line like the following:

gpsbabel -i magnav -f Companion_Waypoints.PDB -i geo -f geocaching.loc -o magnav -F merged.pdb

Second, you must use the installer to install your new PDB file.  Don't
make the mistake of copying it over the existing Companion_Waypoints.PDB
file; the one on the handheld will overwrite it rather than merging with
it.

Finally, because NAV Companion is not designed to work with desktop 
applications, you must tell NAV Companion that its waypoints database 
has changed out from under it.  One way to do this is to go to the 
waypoints screen and attempt to scroll; that will force it to reread 
the database and fix the record pointers that it keeps on the heap.