A Googler has explained that links coming from .edu domain names do not receive greater attention than a link from any other domain name extension.
A reason for why people may have believed .edu links are more valuable may be due to the reason that many .edu domain names have high Google PageRank or rank well. But then again the authority of PageRank via the Google Toolbar is a whole other subject. In short, if you are trying to get links don't just focus on .edu sites. The Internet is filled with valuable web sites willing to link to yours.