I'm in the process of converting some books to ePub. Determining what software to use and how best to go about it has been quite eye opening. Bought Liz Castro's books, but have only just begun reading them. Other resources so far are:
Sygil
TextEdit
Automator
PayPal
Kagi
Kinkos (FedEx Office)
Wondershare PDF to EPUB for Mac
The EPUB Demo Kit and Tutorial
http://www.macosxautomation.com/lion/epub/demo.html