This is a common misconception that a lot of people have. Due to .gov and .edu 'out of the box' trust and most often high PR ranking, people try and obtain these links. There has also been several "Blackhat" techniques used to make your page appear to be linked to .gov sites for this reason. If I'm not mistaken, Google and other search engines have degraded links from .edu blogs, and these types of links do not pass along the high PR of the .edu site. You would be better off trying to get links from top level relevant web sites.
A good page on this topic can be found here
Links from .EDU and .GOV Websites - What are Trusted Top Level Domains
.edu and .gov
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