Windows Defender, Microsoft's free anti-spyware program that's been in beta for more than a year, will shift into its second round of testing in the next two months, developers for the Redmond, Wash. company said recently in an online chat.

Defender is the new brand name for what Microsoft still calls Windows AntiSpyware, the add-on that's been in Beta 1 since it debuted more than a year ago. Beta 1 only works in Windows XP.

Windows Defender Beta 2, on the other hand, will be available for Windows 2000, Windows XP, Windows Server 2003, and Windows Vista, with additional editions for earlier Windows posted at some undisclosed future date. It will be included with both the client and server versions of Vista, Microsoft's next operating system, which is to unveil late in 2006.

Among what's new in Beta 2, said the developers, is integration with Outlook, Microsoft's e-mail client, to scan incoming attachments (Beta 1 scans only files retrieved through the browser), a totally-redesigned interface, and automatic updates that include both spyware definition updates and upgrades to the scanning engine, allowing Microsoft to update the software without having to explicitly release a new version.

The Vista and non-Vista versions of Defender will be similar, though not identical, said Ron Franczyk, a founder of New York-based GIANT Company Software -- the anti-spyware firm that Microsoft purchased in late 2004 -- and now working as a Microsoft developer, in the online chat.

"They are very similar, with Vista's version taking advantage of User Access Protection," said Franczyk.

The long Beta 1 run of AntiSpyware, said another Microsoft developer, was necessary because of the company's plans for the GIANT technology within Vista. "The priority for development has been integration with Vista," said Jeff Williams. "Because Beta 1 was essentially a rebranding of GIANT's very successful and useful product development, focus has been on inclusion with Vista and on the upcoming Beta 2 of Windows Defender."

Previously, Microsoft chairman Bill Gates promised that AntiSpyware would remain free to users; the developers who participated in the online chat renewed that promise, adding that Defender would be free to all users with a validated copy of Windows.