Microsoft launched a beta of its first anti-spyware tool Thursday, beating the self-imposed mid-January deadline it gave itself after it acquired Giant Company Software last month.

The beta, which was expected Thursday -- the Windows enthusiast site Neowin first broke that news earlier this week -- can be downloaded free of charge from the Microsoft Web site.

Also Thursday, Microsoft announced that starting next week, it would provide a monthly update for a malicious code removal tool that would delete the newest viruses and worms from users' PCs.

The spyware software, dubbed Microsoft AntiSpyware, scans PCs for known spyware and then deletes it, said Microsoft, but also can guard the computer against real-time efforts by spyware to sneak onto the system. Rather than use a research lab to identify developing threats, AntiSpyware will rely on the SpyNet community of users, which was set up by Giant, to feed Microsoft with tips on new adware and spyware.

"[Customers] have made it clear that they consider spyware and other deceptive software a major concern in their environments," said Mike Nash, Microsoft's corporate vice president in charge of security, in a statement posted online. "They're looking to Microsoft to help."

Downloading AntiSpyware can be a chore, however, since Microsoft's pushing its Windows validation as part of the process. The procedure, which Microsoft first began using in September, requires that users locate their 25-character Windows Product Key to prove that their copy of the operating system is legit. Users can bypass this requirement at one point in the several-screen process, however, and get to the download a bit more directly.

While Microsoft touted AntiSpyware's prowess, analysts and competitors in the security spyware business had differing takes on the company's entry.

Symantec's Vincent Weafer, the senior director of the Cupertino, Calif.-based security vendor's virus research team, took the high road. "I think what Microsoft's done is a natural progression of what they've been talking about for months," he said. "The more awareness there is about spyware, the better it will be for everyone.

"At this stage, Symantec is quite positive about Microsoft's move," he added. But he left the door open to later disagreement with Microsoft's strategy if it came down to its partner taking dollars and cents out of its profit line. "When they get to the point were they're talking commercialization [of the technology], when they have more details on that, we'll have more to say," said Weafer.

Webroot's vice president of threat research, Richard Stiennon, wasn't so coy. Webroot, which makes and sells consumer and enterprise editions of its own anti-spyware software, Spy Sweeper, has more to lose if Microsoft squeezes out rivals already in the spyware space.

"Microsoft's tackling spyware with a very simplistic, first-generation product that looks only for spyware fingerprints," said Stiennon, who questioned the effectiveness of its reliance on users to spot spyware. "They'll still have to follow up with a big team of researchers," he added, to compete with long-time suppliers of ant-spyware technologies.

"In the short term, I think it validates the concern about spyware, but I think the SpyNet process has the potential for significant numbers of false positives, and Microsoft will face a battle in convincing people that it's not collecting other information from their system if they contribute to SpyNet," he said.

"Microsoft's rock really is coming into this pond," said John Pescatore, the vice president of Gartner's security research group. "What this will do in the long term is drive down the pricing of anti-spyware software in the enterprise. All these companies, like Computer Associates [which recently purchased PestPatrol] and Symantec and McAfee were hoping to make money by charging another $30 per seat for a spyware add-on."

That won't be possible, Pescatore predicted, with Microsoft able to push prices down. "Even if they lower them 20 percent, it's still down," he added.

Microsoft's new effort to first consolidate, then regularly update its malware removal tool makes good on promises it's made at various times, starting in 2003 and running through 2004, to release new cleansing utilities quickly. Such promises haven't always been kept.

"Customers have told us that they need solutions that make it easier to keep computers protected from emerging and ever-changing threats," said Microsoft's Nash.

The worm and virus removal tool, which will first appear next Tuesday, January 11, will be updated as necessary each month on the same second Tuesday that Microsoft uses to release patches for Windows and its other products.

Users will be able to obtain the tool via Windows Update, the Microsoft Download Center (for enterprise customers), and through an online interface, said Microsoft.

"But it's still only a removal tool," said Pescatore. "You still need to have something that can detect viruses and worms."