Available immediately, the new version includes a new protection engine and inspection system. The beta version includes the following features:
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.
The beta is available now at Microsoft's Connect download site.