Stolen Ipod, What should I do?

I live in NYC and my very best friend was pushed against a gate and robbed of his 160 GB ipod (this ipod came out years ago and is discontinued). This happened mind you in broad daylight in front of pedestrians who stood there and did nothing, as well as the boys in blue who did the most wonderful job of just standing there and watching him cry. I can't help but feel helpless because he loved his ipod and he has done so much for me. Now I have to do this for him. Can anyone give me any advice on what he or I should do? He wanted to go on apple and register it as stolen (he registered his ipod when he first got it) but he's afraid it may not work since he cant remember the serial number. I, on the other hand wanted to write to someone from the company to see what could be done about it. Input from anyone would be great (getting a new ipod is a last resort ppl remember they're not exactly cheap,especially not the one he had.) Thanks