since the phones are alraedy unlocked, they must be jailbroken unless a sim proxy is used, i.e turbosim etc.
Originally Posted by shrimp500
and yes unlocked iphones CAN be used with any GSM network worldwide.
Currently only 2g iphones are software unlocked, 3g iphones can be unlocked by means of a sim proxy, but no software unlock is available for 3g yet..
What i do recommend if ur getting the 2g, as soon as u have it in ur hand do a DFU restore to version 2.2 and then use quickpwn/windows or pwnage tool/mac to do the unlocking, activating and jailbreaking.