I still don't understand how the majority of people haven't realised.
Sell 3G on an auction site or forums.
Go buy 3GS on PAYG and just stick the sim in.
SO many people think you have to buy your contract out then sell the phone and get a new contract, madness.
(Not directed at the OP but you can try selling your phone and just buying 3GS on PAYG and use like I said)
I still don't understand how the majority of people haven't realised.
*snip*
I think I saw that O2 will give you £170 for an 8Gb 3G and £180 for a 16Gb 3G but I can't remember where I saw that. It's a rubbish price.