If you reset your phone, you have to plug it into iTunes to connect back to it. However, this will depend on the iOS version that your phone is using since for the updated iOS 6, you do not need to connect back to iTunes for its configuration. Make sure that you create a backup before resetting your phone.
Hello It depends on what iOS: For iOS 6 you don't have to, you only need the micro sim and start configuring the phone. For the other iOS you have to connect it to iTunes to configure and start. Goodbye