[Update: we now have an official feed for the main PDC event page, in addition to the community/blog feed below]

The Microsoft Communities team was kind enough to create a special category for MSDN blog posts relating to PDC 2005.  If you want to keep an eye on MSDN bloggers talking about PDC, subscribe to:

http://www.microsoft.com/communities/Rss.aspx?CMTYSvcSource=MSCOMBlogPosts&Params=%7eCMTYDataSvcParams%5e%7eArg+Name%3d%22CategoryGuid%22+Value%3d%22b86a2345-58d9-4330-8b5b-29b26923e7d2%22+%2f%5e%7eArg+Name%3d%22CultureCode%22+Value%3d%22en-US%22+%2f%5e%7e%2fCMTYDataSvcParams%5e&NumberOfItems=50

It's tempting to try to parse all those parameters and trim the URL down (and get rid of things like CultureCode), but I'm not sure what's required and what isn't.  I got this URL by going to http://www.microsoft.com/communities/blogs/PortalHome.mspx, searching for individual posts in the category "Microsoft Professional Developers Conference", and then clicking the RSS icon on the results page.

And yes, I can see that the result set is a little cluttered, I will ask owners of un-related posts to re-categorize their feeds so that they don't get aggregated up here.  If you're a MS employee with a blog on MSDN, you can control which posts show up in the PDC feed by using the appropriately named "Microsoft.com Communites Blog Registration" tool.  For my blog, I created my own category feed for PDC related content (http://blogs.msdn.com/jmazner/category/9767.aspx/rss), and then I used the reg tool to link that feed to the public "Microsoft Professional Develpers Conference" feed.