Having attending the PDC in LA, I was one of many attendees that followed the Office 12/SharePoint stream of presentations and talks. Didnt attend the PDC? Check out the online tour over at Channel 9.
Many of the presentations from the PDC are available, those who attended the PDC recieved a multi-disk kit that provides all the spearker presentations and a catalogue. For those who dont have access to the disks, have a look at Site Stream.
Some other sources of information are:
Finally, go to Microsoft Office Online for preview information and downloads.