If you use Verizon Wireless as your cell phone carrier, I recommend considering their free Backup Assistant application for you phone (bandwidth charges may apply, but purchasing the app is free). It will backup your phone contacts and upload them to their Web site where you can add new contacts, edit existing ones, and delete outdated ones. These updated contacts can then be downloaded back to your phone, or even sent to a new phone if something should ever happen to your current one. Read more about it, here:

www.verizonwireless.com/backupassistant/