Google Sync is a free online service for backup of your contacts !
How Does Google Sync Work ?
Google uses a protocol called Microsoft Exchange active Sync for providing majority of the synchronization services. It also uses a method based on SyncML for other phones.
By activating Exchange synch, you can sync your contacts, calendar, email, task.
I activate it with my Google account. I am using these settings on a wi-fi connection and they work very well.
Exchange active synch it'll ask you for you network. There you select your wi-fi connection and then in server settings...