Sounds really interesting, Bob! For reasons unknown to me PalmOS development has never been a widespread topic. I don't think it is hard to write programs for PalmOS if you have programming knowledge, mainly because the device is so much smaller (in functionality) than a normal PC.
However, I wouldn't go for anything but C programming. Platforms like Java (or here: SuperWaba) are generating programs that are usually uncessary big in size and take more CPU than a program that was written in C. You could go either with some open-source C compiler, or pay for a more advanced solution. Some interesting programming links:
http://prc-tools.sourceforge.net/
http://pilot-link.sourceforge.net/
http://www.zenonez.com/prctoolsx/
http://www.flippinbits.com/palmdevfaq/
http://groups.google.com/groups?as_u...ot.programmer*
http://www.palmos.com/dev/
http://www.palmos.com/dev/tools/gcc/
http://www.gnu-designs.com/palm+linux/ (guy behind Plucker!)
http://www.palmos.com/dev/support/docs/
Tell me what you think!