Microsoft has announced that "XP Mode" for Windows 7 has reached the Release to Manufacturing (RTM) phase. The completed version will be ready for download in exactly three weeks on October 22 -- the same day Windows 7 will hit store shelves. This is good news for OEMs looking to provide Windows XP Mode for their customers from the get-go.

Windows XP Mode is essentially a virtual Windows XP environment running under Windows Virtual PC. It is mostly intended to allow small and mid-sized businesses to use old software that is incompatible with Windows 7 during the transition from Microsoft's dated operating system. Redmond insists that many XP programs will be compatible with Windows 7, but XP Mode is something to fall back on for those that aren't.

If you're running Windows 7, you can download the Release Candidate (RC) of Windows XP Mode on Microsoft's site.