Xbox's Major Nelson has links to more Xbox team bloggers:
"When I started this blog over two years ago, no one in the Xbox product team was blogging. I launched this blog in 2004 after I joined the Xbox team as a way of sharing a little bit of what goes on here at Xbox, as well we other things that I personally find interesting (like gadgets.) Since then, it’s become rather successful (1.7 million hits in the past 4 days !) Recently, a few other people around the Xbox division decided to jump in and start blogging."