tedster - 11:48 am on Oct 19, 2010 (gmt 0)
What you heard is a kind of myth or misunderstanding. Google does not give an extra boost to a link just because of the TLD of the linking page. However, it happens that .edu and .gov domains often have high authority, well linked pages. It's the strength of the page itself that gives value to any backlink, not the fact that the TLD is .edu or .gov.
The same algorithm applies - if a link is nofollow, or if the page is penalized - then the link doesn't give you any help. If the link is in the content area of a page and freely given - that's where you'll see maximum value.