Don't you have to publish through Smashwords or Lulu to get your ebook on the iBookstore?

No, once you convert a book to the proper format, you just have to go through the process with Apple to get it up onto their store. As an author or publisher you want to get it done professionally, but if you are converting for personal use you can use software that will give you a rough copy in a different format.

Originally Posted by damon45

Calibre and sigil is two good tools you will need to create and edit eBooks. But if you have multiple documents to form your ePub eBook, you need to use an ePub creation software which will allow you to make an ePub book from different documents or combine them and set related book info in order to make a standard eBook.

I don't know why Calibre works not well with line breaking and often wreck the layout of my original files. But I have to say it's one of the most used open source for creating ePub files.

I use Calibre and sigil for checking my ebooks. I use Calibre for converting ebooks to different formats, from ePub to PDF or vice-versa. I use Smashwords for creating my ebooks, and upload my own MSWord doc files to Amazon for conversion. Both Calibre and sigil require some knowledge of HTML if you want to fine-tune your ebook.