This script converts the files of the selected tracks in iTunes using an encoder of your choice on-the-fly (restoring your Preferences-set encoder afterwards). The newly converted files are then moved to a new location of your choice, and their tracks removed from iTunes.
OS X 10.6.8 or better.
Also see ConvExp to Album Folders.
Convert selected tracks and replace them with converted versions
Remove iTunes tracks disassociated from files
Set year of selected tracks to their release date's year (if available)
Resample selected tracks' artwork to user-set size limit
Remove all artworks from every iPod track
Batch-reset the Start and Stop Time of selected tracks to their entire duration