If you are on Orange, there is a product called "Contacts Backup" you can use. Download it free from the App store and then on your next handset, download Contacts backup and press restore, I am sure there will be some free apps you can download that can enable you to do this. Contact2sim is another good one which is free but I know it's on the Android Marketplace but I don't have an Iphone so not sure if it on App store.