I am from the US but live in Vancouver for grad school, so I travel back and forth between the two countries fairly regularly. I have an AT&T account and am eligible to upgrade to a 32 GB iPhone 4 for $299. If I buy one of the unlocked Canada models, it looks like it is going to be around $750 or more, according to estimates. I have never had a jailbroken phone (or participated in a forum such as this), and I have some questions. I would really appreciate any help anyone could offer. 1. I talked to Bell (my Canadian carrier) today. I asked them if I had an unlocked US iPhone 4 if I could get a mini SIM from them and everything work. The guy consulted his supervisor and told me that I can certainly get a mini SIM when they are available next month, but there is a chance that the data packages and features will not work. A) Is it a realistic possibility that the data package would not work or are they just covering themselves? How likely is it not to function? B) Is it a realistic possibility that features of the phone would not function? How likely is this? 2. Will my jailbroken iPhone 4 continue to function (and function properly) when I am in the US and have my AT&T mini SIM inserted? 3. I gather that different versions of the iPhone require different jailbreaking procedures/software. Will there likely be a jailbreak for the iPhone 4 in the near future? 5. Could my iPhone 4 become "bricked"? 6. Will Apple continue to guarantee the iPhone / honor Applecare if I unlock an AT&T iPhone 4? 7. Are there other factors that I have failed to mention that I should be considering? Thank you tremendously for reading this post and for any guidance you could give on any or all of the questions above.