I have a Blackberry Bold on Verizon with 700 minutes and unlimited texting/internet use. I want to buy an unlocked iPhone 4 and put the sim card from the blackberry into the iPhone. 1. Will it work fully functionally as any other iPhone 4? 2. If I do that, would Verizon charge me more? 3. Would a "BAD ESN" iPhone4 work? 4. Any tips on what specific kind of unlocked iPhone 4 I need to get? (ie if it was an at&t iphone, would I be able to use it for my previous stated purposes?)