Treonauts: Alarming your Treo points to a couple alarm apps for the Treo.
I got here by beginning a hunt for a timer-based audio on/off program for the phone. I keep forgetting to turn the phone ringer off when I get into the car and then forgetting to turn it on when I get out of the car.
A few more links:
Utterly off topic, but HOLY COW! Google Maps for the Treo: Kmaps. Requires a Java engine on the handset, which must be installed by the user, so I haven’t yet done this (my twiddling and dinking time is even more limited than my blogging time).