Create an iTunes account:

To configure your iPhone, you will need an account in the Apple iTunes Store.

If you already have an account, please verify that you know your user name, as well as your password. If you do not have an account, you should create one as of now, as to save time later on.
To open an account, launch iTunes, select the Open session button, in the upper right hand of the page.

Create you account and you are ready.