Both Apple and Microsoft also have plans to provide free or nearly-free upgrades to their new operating system for customers who purchase a computer in the months before the OS releases.

Apple announced its program, called today, saying the people who buy a qualifying Leopard-powered Mac between June 8 and Dec. 26 will be offered a copy of Snow Leopard for a $9.95 shipping and handling charge.

Microsoft unveiled the name of its program -- -- but little else last week. Other sources, however, have been reporting since January that the deal will run from June 26, 2009, to Jan. 31, 2010, and provide free or discounted upgrades from Vista to Windows 7.

Apple's Snow Leopard announcement came at WWDC, where company executives, led by Philip Schiller, Apple's head of marketing, also launched a top-to-bottom and introduced the .

As expected by many, though not all, analysts, CEO Steve Jobs, who is on medical leave until the end of this month, did not make an appearance.