TechEd04 presentations gone?

The TechEd 2004 presentations were online for a while. I now get a lovely 404...
Hitting the root now shows a password prompt instead of redirecting to the above url.
Even the PDC2003 slides now appear to be gone ("This content is no longer available online.")...

What's going on? :(

Update: Some slides are still available around in MSDN, at least for Visual C# and ASP.Net. (without any audio/video, at least yet).