Stanza

Stanza is a program for reading eBooks, digital newspapers, and other digital publications. The software supports the eBook formats epub, MS LIT, Amazon Kindle, Mobipocket, and PalmDoc, as well as general document formats HTML, PDF, MS Word, and Rich Text Format.
Stanza features a variety of text layout views, such as multicolumn, vertical scrolling, and horizontal scrolling.

Significantly, Stanza also supports exporting to a wide array of formats for use on the Apple iPhone using a bookmarklet technique, as well as mobile devices using 3rd party readers such as Mobipocket or the Amazon Kindle, and can also export books as audiobook MP3s.