Rob presented the following explanation :
> My iPod Nano is on the brink of dying and i also need a new phone!
>
> I am wondering, is it legal to purchase a iPhone and just stick in my
> exisiting o2 simcard - as i have a brilliant deal from o2 and i am not
> prepared to spend more money for less minutes!
>
> Also would the phone need unlocking or not since i have an o2 customer?

AFAIK, to have it (properly) activated in the first place, you have to
sign up through iTunes when you initially hook up the phone to the
internet/pc.

After that, you should be able to put any O2 SIM in it, however, you'd
have one too many contracts at this point.

The alternative is to unlock it yourself after which you could then
insert your existing SIM, invalidating the guarantee - make sure you
don't subsequently let it activate through iTunes afterwards as it will
re-lock itself.

All AFAIK.....