Aborting process during Spotlight
I noticed mdimport process running on my G4 as well. You can count on it after a backup or a large file transfer. After running my backup, mdimport is active for just a few minutes. I see the activity light going on the front of my external drive after the backup completes. Then, it's done. I would say give your machine the three or four minutes it needs to run this process, it will finish and get out of the way on its own.