Mini-Microsoft (Anonymous Microsoft employee, no holds barred! Critical, but fair.) (from waxy.org)
MSDN's Channel9 (This is site is probably "duh" for MS-savvy people. But I didn't even know it existed. Developer videocasts, marketing stuff, and lots of interesting free education. I like it.)
Business Week MS-centered podcast (mp3. About Microsoft's complicated identity, and blogging employees!)
The best interview with Bill Gates I've ever heard or read. (mp3. Or transcript. I've never heard the enthusiastic part of him before. Excited without being defensive. Talks about the emerging, transparent relationship between consumers and companies a little in the beginning. Listen closely. And lots of talk about RSS.)