If you dont back up your cellphone contacts on your desktop/laptop, there is a great service available that backs it for free online.
"ZYB.com" let's you back up your contact information - and even your Google Calendar events - over the air, for free. No cables, no cost.Just go to their web site and open an account, then set up a simple process on your phone to sync whatever portions of your phone you wish. Remind yourself to sync it every now and then to keep current.