Here's my story: I leave the country... tomorrow. And want to use an iPhone in a new country. So, I jailbreak and unlock mine. I don't use any other apps, don't do anything different than my normal routine, just a new carrier for the year. I come back to America in 1 year, and I buy the new iPhone, whatever model it is. I back up my jailbroken one, sync that backup to my new iPhone, and I have all my texts, call logs, pictures, everything easily sync'd onto my new phone. Question: Do I also have the jailbreak files on my new phone? I don't want those - I don't want Apple to think I voided my phone warranty, when I didn't (well, I did for my iPhone 3G, but that's two years old by now...), and I never plan on using a jailbroken iPhone again.