We've covered the issue tangentially before, but in case our guides on EPUB and the process itself haven't been enough to inspire you would-be authors to self-publish your book in iBooks, Greg Mills has a step-by-step guide just for you. Of course, the hardest part may be actually writing the book, but once you've gotten that out of the way, you're just a format check, a registration, and an upload away from becoming an e-published author.
It's really not complicated, and while there are a few hoops to jump through (you need to make sure that your files match up exactly to the store's format, and then, of course, you need to let Apple know that you're legit and responsible), Mills' steps make the process almost completely transparent. The toughest part (besides the technical tweaking and forms to fill out) might be going through the ISBN application process, but even that's just standard bureaucracy.
It's pretty amazing that with just a standard Mac, a little patience, and the right information, almost anybody can publish on Apple's iBooks store. If you go through the whole process and get a title published, send us a tip, and let us know how it went.