They are the same as other links in terms of value, it depends on:
1 - Number of OBL's
2 - PR of page
3 - Content on page
What makes .gov and .edu links more valuable is the fact that, by nature, .edu and .gov links are much more likely to be linked to from other high pr / authority domains.
.edu and .gov links are not magical. A normal edu links with 0 incoming links into it is no more valuable than normal .com link with 0 incoming links into it.