Windows 7 RTM (Release to Manufacturing) is now available at MSDN Academic Alliance.
If your academic institution is a member of the MSDN Academic Alliance you can sign in and download certain Microsoft Software for free. This now includes the full (not RC) release of Windows 7.
You need to acess the MSDN site via your academic institution to be able to log-in.
edit: (just in case it gets lost in the thread)
If your institution is not a member of the MSDN Academic Alliance you could still get access by joining the IEEE - costing US$13.50 for a half year membership.
"Membership in the IEEE is open to individuals who by education or experience give evidence of competence in an IEEE designated field. The designated fields are: Engineering, Computer sciences and information technology, Physical sciences, Biological and medical sciences, Mathematics, Technical communications, education, management, law and policy."http://www.ieee.org/web/membership/students/index1.html