Link building (what form?) and .edu\.gov links

Is it true that to build value backlinks the links need to be in the form of text that has the link attached to it, or it http:// or wwww.whatever.com okay?

I thought I read that it has to be in the form of text. For example one of my sites is Fairmount Pet Service - so those 3 works should be set up as a link, or is www.fairmountpetservice.com okay? There are sites where only the http or www versions are allowed, and I think they have helped raise my Google PageRank to 3. Any thoughts?

I ask because I'm about to embark on getting some .edu and .gov links and would like to do it correctly. As a side question, anyone have advice on getting those type of links? I'm going to ask some of my clients to post a link to my website on sites of their Alma Maters.

Thanks for any & all help!
Jim