do i need an o2 sim card to jb and unlock the iphone?

[cambridgew10]

so this is my dilemma:
just bought a brand new 3g iphone off ebay.
and want to use it with my exsisting tmobile sim.
will i need an o2 sim card to start the process off jb and subsequently unlocking the phone?
basically once i connect the phone to the pc will itune recognise it without a sim inserted?
see what i mean? i just dont know if i need to activate the phone before i can do anything.
thanks

 

[Sy1441]

No you wont. If its a brand new 3G running firmware 3.1 then you cant unlock it at all at this time.

 

[cambridgew10]

No you wont. If its a brand new 3G running firmware 3.1 then you cant unlock it at all at this time.

so u saying that i can just connect the phone and get on with the jb and unlock? yeah i hope is not 3.1!!
thanks