Posted: 2007-11-17 09:07:44
There's always the "unlocked" or "hacktivation" method. In order to keep my business account I went and hacked my iPhone so I could use any SIM on the AT+T network. Not sure which SIM cards would work in the UK using this method, but it's worth looking into. Was a painless process requiring plugging in and out of my Mac while running an app, never had a problem.
This method also allows you to use it as a wifi iPhone without the phone, getting all the goodies the iPhone offers without the phone, and without the limitations and price of the iPod Touch (which I feel is a ripoff, btw). I was on the fence too, but it's just too good of a phone to go back now.