At this time, we only know of one mobile genealogy application that runs under Mac OS 9/X. That would be My Roots
Any applications you can’t install under Mac OS, can probably be installed under Virtual PC for Mac.
For help or information about genealogy on the Apple Macintosh platform (OS9 or OS X), please visit MacGenealogy.org
Articles:
PDA Software for Macs by Laura G. Prescott
linkforum to MacGenealogy.org