Microsoft's web site seems to operating fine, and there's no reason to think that wouldn't last - at least until Thursday the 12th of February, when the DDoS attack of the Doomjuice worm changes slightly.
Filtering web access which not from web browsers seems to work fine to protect the site. Unfortunately, we can expect to see future viruses launch similar attacks with some generic "User-Agent: Mozilla" string.
The number of scans for port 3127 are steadily increasing at incidents.org.