Hijack iTunes 

Hijack iT! is a tool for automating the conversion of audio files in iTunes playlists using Audio Hijack Pro.

Using Audio Hijack Pro on it's own you can not easily convert, apply filters, etc. to multiple tracks from iTunes in an automated fashion. This tools allows you to setup an Audio Hijack Pro template that not only can be used to convert media, but can also be used to apply sound effects/filters to the music, break the audio files up into conforming sizes (every 30 minutes or something) for long files, etc. When you launch the tool and select a playlist each track in that playlist will be captured using the Audio Hijack Pro template you have setup. Each track will be named properly and saved in the location defined in the template. There are quite a few formats supported by iTunes that many digital players don't support and some that are simply non-standard and/or proprietary. This makes converting those formats to standard, non-proprietary formats simple and automatic.