Might see several of these threads after iPhone 4 is released, but my friend is getting an iPhone 4, and will be giving me his iPhone 3GS. My question is this - It is an O2 pay and go iPhone 3GS bought several months ago, I also have an O2 pay and go sim I currently use in a Nokia 5800 (is a fairly new 3G sim btw), will I just be able to put my sim into the iPhone 3GS and it work like that? Or are there things regarded activation or being locked to a specific sim I should know about? What about iTunes, is it linked to his PC only? Maybe there is even anything else I should know? I heard maybe visual voice mail won't work but that's fine. Cheers guys, I trawled Google and found it difficult to find specific answers.