More recently (within the last month or so), there's been a lot of IT media interest in whether IE10 will be available on Windows 7, but recent platform previews seem to have supported Windows 8 only and Microsoft have been conspicuously quiet on the matter. Just google "IE10 Windows 7".
This isn't to say that IE10 won't support Windows 7 in the end, but right now the picture isn't looking good.
http://arstechnica.com/information-technology/2011/04/micros...
http://blogs.msdn.com/b/ie/archive/2011/11/29/html5-for-appl...