For Iphone,Blackberry, and windows mobile phones, Google Sync allows you to sync your contacts and calendar over the air with your gmail calendar,no need to worry about losing contacts because you forgot to sync with your computer at home ,it updates in the background every time you change or add contacts.
With all the issues of syncing certain phones with macs, google sync is the best way to go,so wether you lose your phone on the road,your computer dies or you just upgraded your phone and don't have time to go home to get all your numbers back, google sync keeps all your contacts at your finger tips at all times, no matter where you are
point your mobile browser to m.google.com/sync