i got a nokia 6230 witch is a vodafone(contract) but i use a pay as u go o2 sim card it was working fine untill 1 week ago when it locked up and would not call in or out a bit of a bummer as that is what fones are for.
try http://www.unlockme.co.uk (Note : Unlocking is NOT illegal your phone provider will do it for you at a cost of around £30)
Hey, Thats killin itfor taht much! just go to www.unlock.nokiafree.org Click on downloads and download the program that'll create a code which'll unlock it ! u got that!