Microsoft has recently revamped it's customer facing Architecture Portal. It now features a selection of sessions from PDC 2008 that are particularly appealing for the architect audience. Sessions can be launched on demand in the same page, maximized to full screen and eventually downloaded.
But wait, there's more!
The Patterns & Practics team has been releasing a lot of valuable material as of late, including new whitepapers or sample kits like the Unity dependency injection container or Enterprise Library v4.1.
In addition to the great content published on the Architecture Portal, you'll also find architect-focused content aggregated from non-MS news and media feeds (e.g. infoQ, Redmond News, etc)
Hope you find these resources helpful!