you can go to AT&T, Bestbuy or apple and ask for one full price, of course the phone WILL STILL be locked to AT&T even though you paid full price for it.
If you want a factory unlocked one you could go to Canada or Mexico and buy one there....
he doesn't care if it's locked. he's not using cell service at all. still, if you're bound by wifi, i'd guess that you're not really walking around with it. headphones and mic (especially bluetooth) don't seem like a big deal to me.
so, what's the best way to activate the phone while preserving push notifications?
I ran across an outfit that sells completely unlocked iPhone 4G's, that are set up for international calling. Just make sure you are sitting down when you see the price
http://www.onesimcard.com/details.php?idgood=218