Microsoft is still accepting beta testers for its "ongoing beta" of Security Essentials.
Security Essentials build 1.0.1611.0 was released to the public at the end of September and Microsoft promised future updates. The beta test program offers a test build named 1.0.1676.0 for download which updates to 1.0.1743.0.
Security Essentials is designed to work on Windows XP, Vista and 7 and protects end users against virus threats and spy ware. MSE is Microsoft's free anti-virus and anti-spyware product that replaced Microsoft's paid Windows Live OneCare subscription service which was withdrawn earlier this year. Neowin exclusively revealed Security Essentials in June when it was codenamed "Morro".
If you'd like to test the ongoing beta then follow the sign-up link below. If you sign-up you should be auto accepted. Thanks to Rafael Rivera for the news tip.