Someone told me .gov and .edu sites are quite good for backlinking. But I have a problem, how can I find .edu and .gov websites to post my links to.
Use Google/SEO footprints. Example of one, keyword+inurl:blog site:.edu Easy as that, just be aware most .edu sites are highly moderated.
Try a Google Search as Mr.Coe has suggested. Note that .edu and .gov sites are strictly moderated. Some don't even allow comments. You might want to consider targeting authority sites within your niche instead. Hope that helps. Have a good day!
totally agree affilorama, building links from high PR edu/gov won't help you if your website niche isn't at least a little relevant. You're better to build links from relevant sites.
I think this post on DP would help you a great deal. It explains all the footprints on Google to find such sites. http://forums.digitalpoint.com/showthread.php?t=2563812
What I would do is grabbing some backlink checker and finding out where top competitors got their backlinks from. And from there it is possible to check out extensions of websites linking to them.