Microsoft announced recently - on Twitter - that it would be offering students an upgrade to Windows 7 Professional version for $30. The deal is very much the same as 'The Ultimate Steal ' deal for Vista, but the upgrade is half the price of that bargain.
Students who are determined to be eligible will get their upgrade to Windows 7 via download, but will have the option to purchase a backup DVD. Buying the backup DVD with the Ultimate Steal offer only cost $9.99, tax, and shipping, and this will probably be similar.
There is some speculation that this is a response to Apple selling Snow Leopard for $29, and a bid to get students to choose Windows over Mac.
Microsoft has students apply for the program using an .edu email address, and has a list of acceptable institutions that don't have email with that suffix. To find out if you are eligible without an .edu email, Microsoft requires you fill out an online application and 
supply proof of your student status.
Eligible students are allowed to purchase one copy of either Windows 7 Home Premium or Windows 7 Professional from the online store, per the Microsoft FAQ.
Clicking on the FAQ is also the way you begin to apply for the Windows 7 upgrade, as the links for enrollment are in the popup window for the FAQ.
The regular upgrade to Windows 7, for non students or those who are not taking advantage of the upgrade from Vista program, is $120.
The offer to students to get the upgrade is valid through January 3, 2010, at 12 am CST. Find the Student Windows 7 offer here. This is an excellent option for students who already own a computer and have had Vista for some time.
Technical students, whose schools or departments are members of MSDNAA, are able to download Windows 7 for free, through Microsoft's arrangement with the schools. You can check to see if your school participates in the program on the School Search. This program is available both in in the United States and Internationally. There is also information at the link above to find out if your school can join the program. One other plus for students whose institutions are members of MSDNAA is that high schools can also participate. High school students were not eligible for the Ultimate Steal deal.
These are the best choices for students who want Windows 7, who don't purchase a computer with Vista installed between July 29, 2009 and January 31, 2010. That offer does extend for a longer period than this student deal, and is the best way to upgrade for people intending to buy a new computer during that time period, if it has any version of Vista installed except for Home Basic.