@ "Palm aps"
Well i just (yesterday) installed GarnetVM (Virtual machine for palm aps).
The calendar is (i tried both available for this VM so far) besides ugly - (because in a lower resolution) nothing special.
No usable text in "monthly" view.
Besides it crashed, when i tried to turn off the sound.

@ "no PIM"
KdePIM is a highly configurable PIM with an intuitive calendar (KOrganizer) running under Qtopia. There is an ARMEL port available (i asume GPL is also valid for a company?) on debian.org. I guess it shouldn't be too difficult for a programmer to get it running on Maemo?