A beta release of Windows Live OneCare 2.5, Microsoft's automated security suite for home users and small businesses, is available for testing from the Microsoft Connect Web site. Microsoft stated through its blog that there is little apparent difference between the beta and standard versions.

http://windowsvistablog.com/blogs/windowsexperience/archive/2008/04/07/windows-live-onecare-2-5-now-in-beta.aspx 

Urs