ZYB is an easy way to backup your mobile while allowing you to share and manage important data. No wires, no software, no hassles. It’s free and easy and it takes less than a minute to get started. With ZYB you can sync your contact lists and your calendar wirelessly at any time you like, practically anywhere in the world. ZYB works over most types of networks and does not require installation of any proprietary software on the mobile itself.
This is one of great online tool i came cross & this is very helpful to me. This has synchronized my SonyEricsson K750i contacts without any issues.
Check supported phones whether your mobile model is there or not 
wow,, it is too nice
i got it working with out any trouble.
thanks for the info
You are welcome Ati