This takes any (long) playlist in iTunes, breaks it into equally timed playlists and creates these playlists on your iPod (which also means the files are copied to your iPod if they aren't already there.)
- If your daily commute is 30 minutes one way, then make multiple 30 minute lists. Listen to a different list every day until you have heard all the music on your iPod.
- Make 45 minute playlists for 45 minute exercise periods. Listen to a new playlist each day.