USA:
Windows 7 US Online Store - Student Registration
UK:
Windows: Student Offer
There was a bit of confusion yesterday regarding the recently announced Windows 7 Academic
pre-order special, hopefully this post can clear most of that up. In short, if you're in the USA or in the UK and still have a valid .edu email address (or an address associated with an affiliated academic institution) then you're eligible to purchase an upgrade edition of Windows 7 Home Premium at the above links for $30 or £30. The offers vary a little bit, as the USA site is currently active, while in the UK you'll have to wait until October 1st to make your purchase. The UK site also mentions the Professional version of Windows 7, while USA appears to be Home Premium only. Both offers are good for a limited time (through the end of the year), so if you're interested in this you should act sooner rather than later.
Also, the only check on this offer is the email address; many institutions keep your student account active long after you've graduated (or left), so it's worth making a visit to your school's student services or office of information technology page.
Keep in mind that this is for a digital copy (which you can download and burn to disc yourself), it's an extra $13 for a DVD copy shipped to your door, but all things considered it's still an incredible price compared to the MSRP of $120 for the Home Premium Upgrade edition.
UPDATE: You can get the Professional Edition via this deal. The default choice is Home Premium, however when you select it there should be an option underneath prompting you about network settings (or something similar, I'm not sure off-hand). Choose this and it will change to Professional.
Via:
Get Windows 7 Home Premium for $30 With a College Email Address - Deals - Lifehacker bit-tech.net | Get Windows 7 for £30
UPDATE #2: Many people have asked about how to create a bootable install disc from the Student Discount download, follow the link below for instructions.
Make bootable iso from student d/l - Windows 7 Forums