Just saw this over on the Windows Team Blog... it looks like the Microsoft Security Essentials team is keeping busy, the first release is already very awesome, and now we have a beta available for the next version.
New features in the beta of Microsoft Security Essentials include:
Windows Firewall integration – During setup, Microsoft Security Essentials will now ask if you would like to turn the Windows Firewall on or off.
Enhanced protection for web-based threats – Microsoft Security Essentials now integrates with Internet Explorer to provide protection against web-based threats.
New protection engine – The updated anti-malware engine offers enhanced detection and cleanup capabilities with better performance.
Network inspection system – Protection against network-based exploits is now built in to Microsoft Security Essentials.
To download the beta of Microsoft Security Essentials, click here to visit the Microsoft Connect page to register for the beta. Once completed – you will find the instructions for downloading and installing the beta. We value your feedback – beta participants are encouraged to provide feedback about their experiences with Microsoft Security Essentials through Microsoft Connect. Please note that this is a limited beta available in English (U.S.), Israel, and Brazilian Portuguese (the beta will also be available in China in Simplified Chinese later this year) and is available to genuine Windows users on a first come, first serve basis until the allotted spots for the beta have been reached.