I mentioned the other day that Barnes & Noble, via PubIt!, is getting in on the self-publishing act. It now appears that Apple is doing the same thing; all you need is an isbn, a US tax ID, and an iTunes account. Oh, yeah, and a new(ish) Mac: the Intel chip variety, running OS 10.5.
Because Apple's model places a relatively large number of restrictions on would-be self-publishers, I don't necessarily see the company as the proverbial "go-to guy" for most authors looking to self-publish their e-books. It's much easier to upload an e-book to the Kindle store via Amazon's Digital Text Platform, and the Kindle app on the iPad would automatically make those books available on Apple's device.
Amazon also grants you substantially more flexibility with format, the option of using their DRM (it seems to be automatically encoded into any books sold through the iBookstore), just as many (if not more) options regarding rights territories, and the benefit of knowing what you're getting into (royalty-wise) ahead of time. As far as I know, the details of Apple's royalty structure for self-published material still haven't been hammered out.
Again, I'm not encouraging you to self-publish because, frankly, I think it's still to your disadvantage. (I think it will be to your disadvantage for the foreseeable future, but there are many who disagree with me on that.) Think of it this way: if you're recommended to an agent, you have an implicit seal of approval that means you're going to get that agent's full attention much faster than if you were to appear in the endless query sea through which (s)he slogs so dutifully each day. Likewise, if you are published traditionally by a publishing house, you are going to get the attention of the reading public much more easily than if you self-publish your novel and throw it out into the infinitely larger sea of written material available for sale on the Internet.
I believe that the theory that e-books will utterly democratize publishing is a myth, as is the theory that agents and editors will be out of jobs once the market share for electronic books reaches a certain level. I'm not saying this out of some misguided sense of self-preservation, either; I mean, Christ, I'm in sales. If you can sell books in America today, you can sell anything. If publishing were to finally die tomorrow, I'd find a job selling something else.
In brief: I don't think you should self-publish, but if you're totally committed to the idea, make sure you do your research. Find a good product/platform, do as much as you possibly can with it, and sell yourself and your book as much as humanly possible. Without an agent, editor, marketing team, publicist, or sales rep, no one else is going to do it for you.