In the latest sign that Microsoft expects to support its Windows XP operating system for the foreseeable future, the company on Tuesday introduced a new licensing program designed to let users of fake or pirated copies of the business version of the OS upgrade to fully licensed copies.

Under the plan, called Get Genuine Windows Agreement, software resellers can offer to their business customers a volume licensing contract that will allow them to replace fake or "mislicensed" copies of Windows XP Professional with legitimate versions.

To qualify, users of illegitimate versions of Windows XP Pro must pledge to use only genuine Microsoft software going forward and agree to have their software infrastructure audited. Once they bring undocumented copies of Windows XP Pro into compliance, program participants will have the option of enrolling the software into Microsoft's Software Assurance program -- which offers upgrades and support for an additional fee.

Resellers who push the Get Genuine Windows Agreement to customers will get a cut of any new license fees they generate, Microsoft said. The company did not disclose the cost of licenses to be sold under the program, but indicated that such licenses would be sold separately from existing volume licensing offers.

Microsoft estimates that 35% of all software in use around the world is stolen our counterfeited.

The program may be Microsoft's latest response to the fact that many businesses are sticking with Windows XP, despite the widely hyped launch of Windows Vista in January. Last week, Microsoft said it would allow personal computer manufacturers to continue selling Windows XP through June 2008. The company originally planned to stop shipping the software to computer makers on Jan. 30.

Many commercial software buyers have railed against Windows Vista's price, lack of compatibility with existing software, and system requirements that exceed the capabilities of PCs more than a couple of years old.

PC makers have responded to such concerns by continuing to push Windows XP, despite the millions of dollars that their partner in Redmond spent promoting Vista. Dell, Lenovo, and Hewlett-Packard have in recent weeks gone as far as offering customers discs that effectively let them "downgrade" their Windows Vista systems to Windows XP.