The Palm official list can be found here. The compiled list of the "tons of undocumented features" can be found over at my home away from home, Pre Central.
Highlights So Far?
I haven't had long to play around, but so far, here are a few things that excite me:
1. Links on the web browser select easier and faster.
2. The UI seems snappier in general (likely due to the JS performance upgrades).
3. Okay, shallow, I know, but I love the emoticons in text messages. It's a fun detail.
4. iTunes sync is back! This doesn't greatly affect me, but it's kind of fun in a "Ooo, no you didn't" kind of way.
What's Not New?
It appears as though there are no big new improvements for the average, non-corporate user--improvements that many were hoping for. Namely, there is no video recording, no improved calendar functions (like, being able to add contacts to events), no message forwarding, and no improved cut/paste functionality.