We've been waiting for this for a long long time. Intel have posted details about the McCaslin platform - now known as Intel's Ultra Mobile Platform 2007.

The core of the platform is a new 90nm single core CPU (confirmed as Stealey, a Pentium-based single core processor) running at 600 or 800Mhz with 512Kb 2nd level cache, 400Mhz FSB and some of the new features from Santa Rosa. The most important of which is the support for Enhanced Deep Sleep state. There are two versions of the CPU - the A100 and A110...

The chipset is a modified i945 - the 945GMU which will provide GMA950 GPU - Enough for Vista Aero Glass. The southbridge is the ICH7. What you have is a 2-tier platform that is able to provide enough graphics support for entertainment and if required, processing power for productivity tools like spreadsheet and powerpoint processing. I assume MIDs will use the 600Mhz version to keep the heat down and the UMPCs will use the 800Mhz version (E.g. Samsung Q1 Ultra.)

Credit has to go to HKEPC because it looks like the info they got from their moles was spot on.

Links to the INTEL datasheet & more news here in UMPCPortal.com