Got Gmail? FullContact will help keep all your contacts in sync with your Gmail address book.
Use FullContact to pull in your contacts from LinkedIn, Twitter and Facebook address books and then sync them back to your Gmail Contacts. It will also find and merge duplicates. You can take a picture of a business card and upload it to FullContact; they will transcribe it and add the information to your Gmail Contacts.
Cost: Free (up to 5,000 contacts) and premium ($9.99/month or $99.99/year) for 25,000 contacts and 50 business card transcriptions per month.