hi guys

i was wondering...

i'm with a official carrier for the 3g iphone (orange, switzerland for those who were wondering)...

my question is:

if i get an iphone (3g), let's say from another carrier (swisscom for example), can i still activate the phone with my orange sim?

other question:

i got a 1st gen iphone, but my carrier didn't sell the 1st one only the 3g. is it possible (in theory) to activate it with my sim?