I've been a loyal Palm user for years so I find myself following their development of Access Linux pretty closely.
If you have a Treo 680P or any other P model, you probably can relate to my pain -- any third party app you install seems to throw it in to a tizzy of random reboots. Don't even get me started with what happened once I installed ChatterMail. And yet I can't give up this weird little Palm addiction I have.
Access Linux is intended to significantly enhance the features and functionality of future Treo smartphones with faster UI responsiveness, simultaneous voice and data usage, multi-tasking, better battery life and WiFi capabilities (oh, don't tease me, Palm!). They even promise backward compatibility to existing PalmOS apps.
Here's a video I found demo-ing Access Linux. It's very iPhone-esque:
Now we just have to wait another 9 months or so for it's release. That's like 7 years in smartphone years.