Some news: Pearson (parent company of Penguin) is buying AuthorSolutions, allegedly the worst of the POD Vanity Presses. (Vanity means you pay a publisher, which is not the same as buying services to self publish). AuthorSolutions -- parent company of AuthorHouse, Xlibris, IUniverse and more) has a pretty bad reputation for customer complaints, at least in the blogosphere.
A lot of people are going to be preparing and publishing their own work in the coming years, so it behooves us all to look into these things.
General rule: if, after trying for commercial or small press publication the old fashioned way, you decide to try self publishing, REALLY self-publish-- that is, hire and oversee your own editor, book designer, publicist etc. Avoid packages such as those from the AuthorHouse companies that don't give YOU the copyright and that charge a lot for finished copies of the books. You should be investing upfront in cover, editing, etc. but then buying books to sell for $4 or $5 dollars production costs, not $14 or $15.
There are companies that come closer to real self publishing, you just have to look for them.