Best App for MP3 Books?

Any music player will do that.

 

I like Jetaudio as it has a high speed play mode, that allows you to speed up the audiobooks without making it sound like its being read by a chipmunk.... So I can 'read' the book quicker.

(works better with some accents better than others, and i've found the quality of the reading/recording makes a big difference on how fast I can listen to it and still take it all in)