But in order to successfully convince people to convert to Linux, says Enderle, the Linux community needs to do some heavy lifting, building the programs that make the transition smooth and cost efficient.

"If you don't do this work, you can't be surprised at how few people move to your platform," says Enderle.

It's a lesson many in the Linux community are working to learn by building software that makes it easier to port Windows-based applications and data to the Linux environment.

Mark Hinkle, a vice-president at Win4Lin, an Austin, Texas-based company that makes Windows-based legacy applications work in Linux, says his company is concentrating on the small-to-midsized business segment and is already seeing success.

"It's being done," he says, noting that companies are beginning to make the switch to Linux from Windows. Some of the key selling points that Hinkle and others use in courting IT centers is the total cost of ownership, extending the life of their existing hardware, and giving IT people a choice of vendors.  

Thomas and others are hoping this early momentum builds, and say two factors will play to Linux's advantage when Longhorn debuts and companies must choose whether to stay with Microsoft or explore alternatives.

First, according to analysts, many of Longhorn's graphics and security features will require users to purchase new hardware -- an additional cost and management concern that may dampen enthusiasm for an upgrade. Second, by the holiday season 2006, several different case studies of successful migrations will be out, providing companies with a viable alternative.

"People are freaked out to do this, and nobody wants to be first [to abandon Windows]," says Thomas. "But when you see successful case studies come out and see the ease and the cost savings, it will be an easier sell."

Thomas says many of the cases studies are underway right now, with many users expected to begin reporting their experiences in the next six months.

When these studies arrive -- with data to back up what are now assertions -- companies will realize they have a choice, says Thomas.

"How will Microsoft get people to upgrade to Longhorn when there's a valid competitor?" he says. "I'd be terrified to be the Microsoft manager tasked with that."