There are a number of quality directories where you can submit your articles. My personal favourite is ezinearticles.com. This one site is responsible for a lot of traffic to my sites. If you only submit to one directory, submit it here.
I have been playing with some software called Article Dashboard, which is free.
This software makes it easy for you to setup your own article directory. I setup a directory a few months ago and forgot about it. I had not even finished editing templates, so the directory has some dead end pages I need to fix. However, to my amazement, I went back to check the directory the other day, and found that over 100 authors had signed up to submit content to the directory. There were also 30 or 40 articles waiting approval. I have been getting articles trickling in ever since, and I checked again this morning and have another 20 or so to approve. This is without any promotion of my site. Incidentally, if you want to submit some articles to my directory, you can do.
The site will improve in the coming months (including working on the templates I have not yet touched). In return for submitting your content, you will get links back to your sites in your resource box. These links pass PR and link reputation, so your sites will benefit. As the PR of the article site grows, so will the value of those links back to your site.
To get articles distributed far and wide, I use a tool called Article Announcer. This tool is very expensive, but does the job well. I have also tried and liked a much cheaper alternative which you can read about here.
The value of distributing articles in this manner reach far beyond just the backlinks you get and the traffic you receive from the article directory. You see, other webmasters pick up your content, and publish it on their own sites, giving your article even more exposure, and your site even more backlinks, and traffic.
In addition to article directories, you can also submit your articles to other webmasters.