No, it wont work.
Jailbreaking it wont help since that just allows you to install non-apple approved apps on it and as far as I know there is no current way to unlock it from the 02 network.
The only way, currently, to get one is to get it from 02 or CPW on a brand new account. If you had an original iphone on 02 you can upgrade but everything else has to start from scratch.
Once you have got it you wont be able to make calls etc on it untill you have plugged it into a PC or mac with itunes on it and registered and activated the phone. Once you've done that you use iTunes to manage everything on the phone.