Download 90-day Windows 7 Enterprise trial here:

http://technet.microsoft.com/en-us/evalcenter/cc442495.aspx?ITPID=sprblog

You don't need any activation key since it's built-in. It's FINAL RTM version, not RC.

Notes:

The 90-day Trial will shut down once every hour when you have reached the end of the 90-day evaluation period.

The 90-day Trial is offered for a limited time and in limited quantity. The download will be available through March 31, 2010, while supplies last.

After the 90-day Trial expires, if you wish to continue to use Windows 7 Enterprise, please note that you will be required to purchase and perform a clean installation of Windows 7, including drivers and applications. Please keep this in mind; Windows 7 Enterprise is not available through retail channels.

Was about to post this; downloaded mine a few mins ago, will check it out when I get home.

I am currently running Windows 7 RC, and it works great. With the release candidate, however, you have until March to use it. Hopefully I'll be able to download Windows 7 free through my university by that point.