Double entries while syncing ipad and iphone(2 posts)
This is a guess. I can't confirm it.
Plug in your iPad and let it sync w/ iTunes. In iTunes select your iPad, and go to the Info tab. Make sure Sync Address Book Contacts is checked. Then scroll all the way down that page to Advanced. From there, place a check in the box labeled Contacts in the "Replace information on this iPad" section. This will wipe out all the contacts currently on your iPad and replace them with whatever is on your computer. If it enters everything twice again, you may want to take a closer look at exactly what is syncing.. Oh and then repeat these steps for your Calendar.
Hope this helps - let us know.