Microsoft’s board of directors has approved a share buyback for Microsoft to the tune of $40 billion, with an expiration date of September 30, 2013.

The board also declared a quarterly dividend of $0.13 per share, reflecting a two cent or 18 percent increase over the previous quarter’s dividend. Said dividend is payable December 11, 2008 to shareholders of record on November 20, 2008. The ex-dividend date will be November 18, 2008.

The prospect of such a buyback is certainly not unheard of. "No doubt the company will keep making acquisitions, but once Yahoo  fell through, there was nothing out there likely to move the needle," writes Joseph Weisenthal at PaidContent.org. "Hence a big share buyback was always a possibility."

Microsoft in fact, just completed a previous $40 billion stock repurchase program, returning over $115 billion to shareholders over the last five years."These announcements illustrate our confidence in the long-term growth of the company and our commitment to returning capital to our shareholders," says Softie CFO Chris Liddell.

Fortune reports that Hewlett Packard has also set aside $8 billion for share repurchases. "The buybacks are aimed at restoring investor interest in companies that have had very little to show in terms of growth amid a sluggish tech spending environment," says Scott Moritz.

If that’s the case, don’t look for Google to be making any similar moves anytime soon. They grow almost faster than any of us can keep up with.