Updating iOS but not through iTunes?

Hey all,

I've got a friend I am going to meet ti help JB his phone. He currently has 4.3 installed so before the JB I need/want to get his phone current. My question is, is there a way to manually update the phone by having 4.3.2 downloaded before we meet? Tried to do it last night through iTunes at a Statbucks and the download was going to take over an hour on there network and neither of us wanted to wait that long.

Thanks
David