Earlier this week, Microsoft said the final version of IE9 will require Windows 7 Service Pack 1, as Gregg Keizer of Computerworld reported.

But Microsoft's FAQ on IE9 for IT professionals now says the opposite:

"When Microsoft releases Internet Explorer 9, will it require Windows 7 Service Pack 1?

No. Internet Explorer 9 will install on systems that have either Windows 7 RTM or Windows 7 with Service Pack 1 (SP1) installed."

According to Ars Technica, a previous version of the FAQ said that "Internet Explorer 9 will require Windows 7 Service Pack 1 (SP1). Therefore, organizations must plan, pilot, and deploy Internet Explorer 9 as part of or after a Windows 7 SP1 deployment."

More: http://www.pcworld.com/article/206206/