iPhone 3G OS 3.0 PC User Firstly, there seem to be quite a few apps out there for jailbreaking and unlocking. So my first question is, if jailbreaking only (I have an AT&T contract), which app has had the most success/ease of use? QuickPwn or Redsn0w? Secondly, will jailbreaking the phone unlock the tethering and MMS abilities that AT&T is holding back on? Third, I'm aware that any OS updates will un-jailbreak the phone, but will "syncing" the iPhone with iTunes cause any unwanted problems after jailbreaking? And lastly, since AT&T is on the verge of losing me as a customer as is, if I do decide to unlock the phone will a new SIM be required or is there an app that can be used to open the SIM to the other carrier networks?