Jailbreak and unlock your device!  The only way to truly unlock the potential of your iDevice is to set it free from the limitations that Apple puts on it.  Want to switch carriers (unlock)?  Want to facetime over 3G?  Want Siri on an iPhone 4 or 3gs?  Want Siri to do more than you ever imagined?  Want to run NES, SNES, or Genesis emulators (and even play with a Wiimote)?  Jailbreaking is the only way.  If you're simply looking to sell your iPhone and get the most money possible for it, Jailbroken iPhones sell for MUCH more online.  Just do a search on eBay to confirm this.  I can jailbreak almost ANY iDevice on ANY firmware.  Standard jailbreak will cost $40, unlock (unlock phone for other carriers) is an additional $10.  Unlock is not possible without Jailbreak.  Jailbreak also includes a lifetime of advice on how to do other things mentioned above, such as installing Siri or emulators.  If I have jailbroken your device, I will always be available to answer any of your questions.  Feel free to email, call or text me for more information about Jailbreaking and Unlocking.