There's a Self-Publishing and POD
forum on the Absolute Write message board that could provide some answers (maybe check out the sticky threads).
And, related, there's an Art & Design
forum with sticky threads on how to design book covers, etc.
When I did it (a writing buddy pushed me to get a bunch of previously published stories back out there) it was really just a case of reading Amazon's and Smashwords's how-to guides, to get the formatting right, and uploading 'em. Both systems are pretty easy... the problem is that everybody's doing it these days!