Outlook Cleaner is a free utility for Windows Mobile which can clean and remove duplicate and redundant contacts, appointments, and tasks. In case you have accidently create a duplicate item or when you copied everything to new phone, this is the best application to do a clean up. It can detect exact duplicates, near duplicates (same or different property values) and also keep / merge / delete the duplicate.

How it works:
Contact cleaning works like this:

1. Scan the Contacts database, looking for duplicate contacts.
2. Exact duplicates are deleted.
3. Near-duplicates are displayed for manual merging/removal.
4. You go through the sets of near-duplicates, where you can see all the values which are different, and choose to keep, delete, or merge Contacts.

Download Outlook Cleaner