If you're a developer interested in UMPCs, check out Jason Bancroft's video interview of Aaron Tersteeg, Intel's Community Manager for Intel Software Network--a group that assists community developers building apps for mobile devices. (Hey, Aaron, how about upgrading your ThinkPad to a Tablet PC? :-) )
Looks like Intel has some terrific and growing resources for UMPC developers, including a Laptop Gaming SDK that includes royalty free code.
By the way Aarron Tersteeg has a great blog. It's got lots of UMPC info, including details on Intel's future mobile plans.