Not sure what's out there, but you should look into hacks for Linux-based ports. If you can flash a Linux port to the unit, you've opened up a whole realm of awesome software, software that's free under Public License stipulations. Supposedly Palm is considering a full scale move to an opensource OS (as apparently the Palm OS has been losing ground to Windows CE) so a legitimate Linux-based option may be available to you very soon -- then the hacks will be numerous and awesome.
Here's some stuff I found for Palm, not sure how good though
http://www.palmblvd.com/software/pc/...atesort-1.html
http://www.djajic.com/
http://www.pdamd.com/vertical/tutorials/hacks.xml