How to use first generation iphone like an ipod WITHOUT sim card?

Is there anyway to just get past the "insert a valid sim" screen so i can put music and pictures and use it like and ipod? I DON't HAVE A SIM CARD! I bought this phone from craigslist and restored it…

Added (1). It is att but no one i know has a sim and its connected to itunes but it tells me to activate the phone

You will need to connect the phone to an itunes account before you can use it without a sim card.

Find some one you know with an att sim (assuming its att)