If I'm not mistaken, it is available for download from microsoft windows 7 website.
You will only be able to download windows 7 of any version is if you purchase the full version from them which can range from 79.99 to 149.00 depending of what version of 7 you want, including shipping and handling.
If you bought vista after june 26th of 2009 you are entitled to a upgrade option, you only have to pay for shipping which 9.99 and it will include taxes I asked MS about this and they verified everything that I just stated above.
Last they will verify your key either by website or phone to see if you qualify for the upgrade edition of windows 7.
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