To follow on from this - does an iphone need to be activated (or hactivate etc) in order for an unlock to work? After Blacksn0w having done nothing to my 3G this is the only thing I can really think that might be causing problems!
As long as you can get into the home screen on the iPhone, you won't need to activate it to work. As soon as you blacksn0w it, or when the phone recognizes a sim, then the phone becomes activated.
Hmm. Unfortunately I guess I'm one of the 3G 16Gb guys who's seemingly unable to get any unlock to work then, as opposed to just having been doing something wrong!
No your not the only one. I can't get my sim to activate my phone after blacksn0w or ultrasn0w either. It just says no service or waiting for activation....