I think it's region free. Amazon, eBay and so on all sell it without listing a region, and I'm running Win7 Ultimate on my desktop, I have about 50 updates I can download for pretty much every language out there.
This one was made in the USA and is sold for use in the UK on eBay:
http://cgi.ebay.co.uk/Microsoft-Windows-7-Ultimate-Full-Version-32-64bit-/320712548734My UPC is the same apart from the last digit, which is a 2, the origin is Ireland.