Microsoft finally speak about its Microsoft Security Essentials (MSE) codename “Morro,” here’s some points that wannabe MSE testers and customers need to know:

• Microsoft is making MSE available for public beta testing begins on June 23 at 9am PDT in the US, Brazil, and Israel from http://www.microsoft.com/security_essentials. And will remain open until the release of final version before the end of calendar 2009, and will be a free download in bith 32- and 64-bit flavors for XP SP2, Vista and Windows 7 (including Beta or Release Candidate) systems.
• Microsoft Security Essentials requires WGA validation, which means it won’t be available to anyone using a pirated copy of Windows. But it won’t require registration or personal information of any kind. 
• Microsoft will be updating and refreshing the beta code regularly in the coming months by pushing updates over Windows Update and other Web mechanisms.

Finally, a new study May 2009 by the independent AV-Comparatives group gave Microsoft OneCare (which shares the same engine and signatures as MSE) its highest (Advanced+) rating.

More info: ED Bott