Late Wednesday night, Microsoft shipped its public beta of Microsoft Windows AntiSpyware, which is based on the anti-spyware application previously sold by Giant Company Software. Microsoft purchased Giant in December. Additionally, Microsoft announced that it will soon ship the first monthly installment of a malicious software removal tool that will help customers remove malware such as worms and viruses. The first version of that tool will appear January 11, the same day Microsoft issues its monthly security bulletins.
Microsoft AntiSpyware Preview
http://www.winsupersite.com/reviews/ms_antispyware_preview.asp
Download Microsoft Windows AntiSpyware Beta 1
http://www.microsoft.com//spyware/
Also, Jonathan Hardwick posted some more info on his blog
http://blogs.msdn.com/jonathanh/archive/2005/01/06/348224.aspx