Building links is one of the important marketing strategies you should do to get listed on the top of the Google search. You need lots of direct link to your website to get listed on the top of the Google search.  By following a basic set of marketing principles including content creation, SEO, article marketing, forum marketing, Squidoo lenses, social bookmarking, link building, USFreeads and PPC you can promote your website very effectively .

Google PageRank is directly related to good quality direct links. You can develop good one way and both way free link using the following ways.

Reciprocal Link exchange
Linkmart.net
gotlinks.com
Web directory

Free Links
Forums
Digg.com
Web directory
Yahoo Answer
askville.amazon.com
sphinn.com

Bookmarking
Social networking is one of the easy way to develop direct links to your site. You can select the tag you want for your site in online bookmarks. The bookmarks will be shared with public.
Addthis.com provides an easy way to include all the social bookmarking sites.  

You can get some free traffic using linkreferral social networking

Check this list of social software http://en.wikipedia.org/wiki/List_of_social_software#Social_bookmarking