REMEMBER, I have NOT tried this myself yet. So I recommend we wait for Steve to respond since he was successful.
You should be able to get a gender changer (about $4) at Radio Shack, and a Din-8 to DB9 ($5) printer cable from MacWarehouse. Combining those with the Casio/Palm cable will give you a serial cable that can plug into the Mac and Zoomer.
Then use the ZoomerPC Comm program under SoftPC per Steve's post (I'll add it to the Quick Tips Center when Steve confirms his cable set up or "blesses" what I suggest), and you're set!
Craig de Fasselle (PDA Craig)
PDA Forum Leader
PS. Nice article in Double Tap. :)