] Internet users who type the WindowsUpdate.com URL in
] their browser get an error message. Microsoft has deleted
] the Domain Name System (DNS) information for the domain,
] and it no longer sends traffic to an actual Web site.

According to Reuters, the number of Blaster-infected machines currently ranges from 386,000 to 1.2 million, depending who you ask:
http://asia.reuters.com/newsArticle.jhtml?type=internetNews&storyID=3287116

Microsoft pulls WindowsUpdate.com to avert Blaster