I've played with it a little, but haven't tried anything terribly complicated.
It seems to be derived from the Pages for OS X ePub export.
- Launch Pages on an iOS 7 device
- Select a Pages document
- Tap the Sharing icon (rectangle with up arrow on top right of screen)
- Tap Open in Another App
- Tap ePub
- Fill out author, title genre, etc. in Enter ePub Info panel
- Tap Send
- Choose an app on your device that support ePub
It has problems with some formatting; not all files have exported correctly. But it does try to build a linked TOC, and if the first page is designated on the Enter ePub Info screen as the cover and it has an image, the image does show as the cover on iBooks (haven't checked in other apps yet). Foot notes are supported.