Edu backlinks are really very effective to improve SERP. However, with all the Google algo that are coming down it is better to get backlink wisely.

Here you go with a list of Edu forum where you can post comment. Please keep in mind DO NOT SPAM

PHP Code:
    http://www.egr.msu.edu/
    
http://www.andrews.edu/
    
http://icl.cs.utk.edu/
    
http://www.okstate.edu/
    
http://www.allenuniversity.edu/
    
http://www.addu.edu.ph/webforum/
    
ttp://forums.columbiabasin.edu/
    
http://forum.cgd.ucar.edu
    
http://picola.library.cmu.edu/forum/
    
http://forum.abtech.edu/
    
http://aofa.cs.purdue.edu/
    
http://wwwapps.ivytech.edu/
    
http://bannerforum.colostate.edu/
    
http://gender-it-forum.itec.edu/
    
http://forums.saa.edu/register.php
    
http://academicintegrity-web.clemson.edu/register.php
    
http://access4all.ewu.edu/forum/
    
http://acm.selu.edu/forum/
    
http://acm.selu.edu/forum/
    
http://ai.vancouver.wsu.edu/jige/forum/
    
http://www.stanford.edu/
    
http://www.academia.edu/signup
    
http://www.etc.cmu.edu/
    
http://www.cwrl.utexas.edu/forum/
    
http://cbcl.mit.edu/jmutch/forum/