Firstly, let me apologise if this has been covered elsewhere, there are just too many conflicting threads out there regarding similar situations. Any way, my 18 month 3G contract is about to end (yes I queued for hours on launch day!) and I'll shortly be upgrading. However, I got a really good deal on a 3GS and have had this for a few months. So rather than upgrade to a 3GS, I'd like to go for a £25+£5 (web) bolt on with a free PS3, then just stick the SIM in my 3GS. I suspected that visual voicemail wouldn't work (which has been confirmed somewhat). However the guy in the shop said that my unlimited data wouldn't work with iPhone. I think this is just a case of changing the settings from idata.o2.co.uk to wap.o2.co.uk but I'm not sure - and don't want to be stuck without data / expensive data for 18-24 months. I don't want to unlock the phone in any way either. Can anyone help with confirmation of this?