According to an Amazon product page, Microsoft's Windows 7 Home Premium Family Pack will only be available until Friday, December 31. The $125 bundle (down from $150) includes three Windows 7 Home Premium upgrade licenses – that's less than $42 each, undoubtedly the best value for consumers to upgrade from Windows XP or Vista. By comparison, a single Windows 7 Home Premium upgrade license costs $110 on Amazon, while a full retail copy is $177.

Microsoft launched the Windows 7 Family Pack last October, but supplies ran out less than two months later in early December. Redmond revived the special offer this September, just in time for back-to-school and holiday shopping, but the company didn't say how long it would be available.

With Windows 8 on track for a 2012 release, we're not sure if Microsoft will offer the Windows 7 Family Pack again toward the end of 2011. If you have a few friends or family members running a pre-Windows 7 operating system, be sure to should take advantage of the bundle before it's gone.