Question: Who owns the IP rights to games that are created by students?
What to look for: Ideally, the students should own all copyright and other intellectual property ownership of the projects they create while they are students.
What to do: Decide if this matters to you. Some people don't care, because they aren't planning on selling anything they make as a student anyway. Some people care, but they're willing to compromise on this (maybe by just not using their favorite game ideas until after they graduate) in order to go to a school that is otherwise their choice. For some people, this is a deal-killer.
What to watch out for: Some schools explicitly state that they own all rights to all student work. Probably the most notorious example of this was Team Toblo (a good story to read for why IP ownership might matter to you as a student). Other schools do not have an official policy at all, which is a signal that they haven't thought about it yet in spite of it being a legal and PR minefield. In these cases, proceed with caution, because the rights may be legally unclear and the last thing you need as a student is to get involved in a legal battle. Still other schools have restrictions: they own the rights to anything you create using university resources (such as computer labs or printers), but a project you make on your own with your own equipment is 100% yours, so there's a way to own your work if it matters to you. Mainly, the important thing is to be aware of the official policy before it becomes an issue... and if you think the policy is suboptimal and you plan on attending anyway, consider taking it upon yourself to push for policy change.
Update 11/13/2008: The monthly IGDA column on legal issues gives some insight into IP ownership rights of student work: http://www.igda.org/columns/lastwords/lastwords_Nov08.php
Update 11/14/2008: It appears this is becoming a much larger discussion. A recent Gamasutra article highlights the problem. This blog post is quoted and linked to in the article, alongside quotes from Tom Buscaglia, Brenda Brathwaite and Susan Gold... so I'm in good company. Maybe this will eventually become a big enough issue that the "we own your IP" schools will consider policy changes, and the schools without an official policy will get off their behinds and make their policy explicit.