[car]

Easier/spammier methods:

You can look for sponsorship opportunities. Student clubs, academic projects.

School newspapers sometimes have ways to get into print as well. Get published, then reprinted online which includes a link.

Even rougher methods:
Look for forums/blog footprints on .edu's and spam away :). Bleh, I don't do that stuff, but I've seen abandoned forums almost as active as webmasterworld.com :) as everyone with a pharmacy or casino to sell posts full page ads and links.