Skydeck is a free online backup software that safely backups your address book to a remote server manage by Skydeck. This utility also can backup a copy of your SMS messages and call history.
As soon as you install Skydeck, you have to make an online account which you will then later use to access your account using your computer's browser. As soon as you sync or backup online you can edit you contacts as if you were doing it on your phone, since they update each other it makes updating your contacts easy and more comfortable.
You can turn skydeck off to save on data transfer or if you just want to backup on a specific time. Overall I love how Skydeck manages to sync properly with my Curve no errors or multiple contacts problems. I find it very easy to manage and make changes in my contacts logging into Skydeck's website.
Download Skydeck Backup Utility from Blackberry Browser http://m.skydeck.com/