A few quick impressions ...
I picked up the white. It is dead sexy. The plastic back is really nice and doesn't feel cheap or like a step back from the chrome.
I can confirm over wifi (believe this is mentioned in the guided tour) unsure on 3g.
WiFi on planes will be accomplished, I imagine, just as it is on busses, trains, and ferries: the transport has a connection of some sort (satellite, typically) which is shares via a wireless router. Presumably airlines do this because of they can strictly control the frequency, bandwidth, etc of the wireless signal being passed through the plane.