This service will sync the address books in your phone, PC, and numerous web services (Gmail, Windows Live, Yahoo!, etc.), providing you with a single, hassle-free address book.

Keep your contacts in sync - Your phone, your computer and web applications will have the same address book.

Never lose your address book again! - Automatic daily backups of your contacts, so you'll be prepared when disaster strikes.

Keep your address book clean - Your duplicates are automatically removed, or you can merge them with our easy to use tools.

Keep up to date with your friends - Automatically let Soocial update your address book when your friends change their details.

Looks interesting. I'm going to play with this over the next few days and see how it works.

Thanks to Rob T. for the tip.