There are tons of methods to build backlinks for your sites. The best way is to create perfect content that people would like to link with on his or her own initiative. However in practice it is not exactly like this. Or at least you cannot always rely on the fact that your contents is good and people will link to you. You have to do something to initialize the process.

Here are some goodies you can do...

You can make some "midget blogs" on Google favorite Web 2.0 websites, slap an article on it with a link back to your site, publish it and forget about it. These kind of websites include: Squidoo, Hubpages, Blogger, Bloggersbase, Ever, Webs, Devhub, Tumblr, Xanga, Webjam, Weebly, ZoomBlog, Wikidot, Nexo, Rateitall.

Social Bookmarking websites are also good places to go, including: Digg, Slashdot, Spurl, Plime, Dotnetkicks, Searchles, Bibsonomy, Tweako, Yattle.

If you can't stop talking, better grab a camera and record it, another easy way to get a backlink. These kind of sites include: Dailymotion, Videojug, Viddler.

After writing your articles on those "midget blog" sites, you can submit it as documents on these sites and still get away with a link, including Scribd, Issuu, Docstoc.

There are a lot of social networks that doesn't have the no-follow tag in the links on your profiles, including: Friendster, Gather.

Other cool websites you can build backlinks.
Yedda - It's like Yahoo Answers, but it's do-follow.

The new article marketing - The new article marketing just got more badass. Now, it gives you a heavy link juice concentrate and damn fine targeted traffic.

Zug - Tell a joke, get a link.