Microsoft late Tuesday opened its OneCare Live security subscription service to broad beta testing, another step toward competing in the consumer anti-virus market dominated by long-time partners such as Symantec, McAfee, and TrendMicro.

OneCare, which was first announced in May, provides a personal firewall, anti-virus scanning, general PC tune-ups, and data backup tools. While some of the technologies are home-grown, others come from Microsoft's security acquisitions over the last two years, such as the 2003 purchase of Romanian anti-virus developer GeCAD and the 2005 buy of New York-based Sybari Software.

Several new features have been added to the service since it began limited testing this summer, wrote Yoav Schwartz, OneCare's lead program manager, on the team's blog Tuesday. OneCare now backs up to external devices, automatically scans files received via MSN Messenger, and integrates with Microsoft Update for anti-virus definition updates.

The OneCare beta can be downloaded from the Windows Live Ideas site; it requires Windows XP SP2. Like most consumer security software, OneCare will demand that existing security products, such as Symantec's Norton Internet Security and McAfee Internet Security Suite, be uninstalled before it's added to the system.

Although the beta is now available to all comers, Microsoft may limit the number of testers, wrote Schwartz. "As we scale up there may be times when we direct people to a temporary waiting list; these pauses will allow us to see how we’re doing and assess our readiness to scale to the next level."

During the beta test the service is free. Until then, Microsoft is keeping mum on subscription prices. "When the final version of the service is ready to go, we’ll let you know the final pricing details," Schwartz wrote.

Left out of the mix is Windows Defender, the new name for Microsoft's consumer anti-spyware product. Microsoft plans to roll Defender into the OneCare service before it goes final sometime during 2006.