This script will change the file type of the selected AAC tracks to "M4B " and file extension to ".m4b", thus making them bookmarkable. (That is, the track will natively resume playing wherever you left off the last time you played it.) Additionally, when used with iTunes 7 or later, deletes and re-adds each track so it will appear in the Audiobooks Library. Ratings, play count, last played date, skip count, and skipped date are preserved.
Perhaps Also of Interest...
downloaded 1m 46s ago
Add or subtract a user-entered number from each selected track's Plays
downloaded 2m 16s ago
Applet assists with swapping, copying, appending data between track tags
downloaded 3m 40s ago
Sort purchased tracks into discrete playlists by name or Apple ID
downloaded 5m 2s ago
Remove iTunes tracks disassociated from files
downloaded 5m 47s ago
Make selected tracks NOT bookmarkable
downloaded 11m 12s ago
Batch set new Last Played/Last Skipped of selected tracks