Glancing at this article and the related Microsoft site, it looks like this is for anyone (in the countries listed below) with an .edu email address (i.e., perhaps not just college students), although you may be required to prove you're actively enrolled if challenged
Microsoft is offering Office 2007 Ultimate edition for a fraction of the regular price to college students from now until April 2008.
In the US, Office 2007 Ultimate edition is officially $679 but college students can get it for only $59.95.
The same deal is available in Canada and the UK from today while Spain, Italy and France have similar offers form 20 September 2007.
Office Watch readers may remember that Australian university students had a similar offer earlier this year. This wider offer is very similar but lasts a lot longer than the Aussie opportunity. The Australian offer had the option of buying a one year use of Office 2007 but this is not available in the US arrangement (the UK does).