systeMacs can help you sync your most important data, contacts and calendar items with
iSync.

iSync works with over 100 cell phone models and your PDA. Simply enter contacts into Address Book and appointments into iCal.

You can add dates and contacts manually on your phone, and iSync will add them to iCal and Address Book. You can also use iSync with your Palm OS-based device. iSync takes care of managing data across your different devices, downloading changes from one or the other and updating each as necessary.