If they are synced with your G-Mail / Google account, the easiest way I know of is to log into your G mail account on a PC. Open Contacts and then under the More button select Find & Merge Duplicates. If they are not synced to your G Mail account, I'm not sure.
Awesome...glad to hear it. For future FYI: it was probably Verizon transferring your contacts that caused the duplicates. If your contacts are synced to your G Mail, anytime you activate a new phone they are instantly synced to that phone.Thanks. Worked like a charm.