I also wrote an article about this very subject recently. And, while I would agree with Anthea Carson that self publishing is more accessible, I wouldn't agree that it is more profitable. To be successful as a self published author, one needs to be more of a businessman/woman than a writer. It's all about self advertising and marketing, which is left entirely up to you. Hubpages is a good model of how one would do as a self published author. If your articles bring in a lot of revenue, you might do well, but if you're only pulling in a few cents per day, your book doesn't have much hope.
In my experience, self published material is almost always poorly edited and poorly written. Writing is difficult and 90% of it is editing, so those who try to bypass the normal channels to become an author give off the vibe that they are too lazy or afraid to truly make their book into something great.
Having said that, I do understand how some writers, who have tried and failed to get published in the larger industry, might turn to self publishing as a last resort.