After a bit of reasearch I have determined that OGG Vorbis is the best format to use for audio on mobile devices. It has excellent compression with great quality even at lower bit rates. To simplify the process of comverting my music, this small app will take an input directory and convert the contained audio files using mmpeg.
The input directory structure will be mirrored in the output directory. For example, album folders will be created if you point the script at an artist folder.