A while back I posted a chm file for the Orcas Object Model... Things have changed a bit since then, so I figured I'd post a new one for the Beta 2 release.
Remember that to view the chm file, you'll need to right click on it in Windows Explorer, choose Properties, and click the Unblock button. There is also apparently some issue with downloading it using Firefox and viewing it in Vista, so don't do this...
SNIP: removed the beta 2 documentation now that the RTM documentation is available.