Well its a bit of a stretch to think of XNA as a mobile technology but since XNA will run on the UMPC it appears to be fair game at the Mobile conference this year. I'm not 100% sure if all UMPC devices are man enough to run all XNA apps but its looks like the closest XNA is going to get to a mobile platform for a while. There's some strange aspect ratios and screen sizes to consider but otherwise it seems like a pretty standard windows install. Nick sent me a link about gaming on the UMPC if anyone is interested.

So if you are in Las Vegas November 5th-8th you should head along and see Nick's talk

MPC310: XNA Game Development for the UMPC November 5th-8th, Mandalay Bay, Las Vegas.

(and how come Nick gets a trip to Vegas and I get Minneapolis !)