Article marketing consists of creating articles from your niche, and submitting them to article directories. At the bottom of each article you write, you are allowed to link to your website. There are quite a few article directories that are very highly respected by the search engines, and having links from there pointing to your site is a huge advantage.
Additionally, once your article is in the directories, other webmasters will come and publish your article. It is not uncommon for one article to get you several high quality backlinks.
I would not suggest submitting to every article directory you can find, but rather just stick with the top few. This would include:
