Repair Disk Permissions

Is there a way to make Repair Disk Permissions run without signing on as Administrator? Possibly having it run automatically once a week on startup or even at a set time each week. The iMacs are running OS X.2 and are in a student lab and we have found that if this runs once a week the computers will not get slow, but we do not have enough time to do this weekly so I was wondering if there is a script or something that would do the job.