[iMore.com]

While iCloud does a pretty good job of organizing and managing our contacts, sometimes things can go wrong. Even if you don't use iCloud, contact management is far from perfect. One of the most common issues people experience is duplicate contacts. You can obviously go through one by one and delete them but if there's a lot, that's not a practical solution. Luckily, there are some App Store apps that help you clean up duplicate contacts in only a few seconds.

Full story from the iMore Blog...