iOS 4 is supposed to ship out sometimes today. This new iPhone OS will bring many new features to the iPhone, including multitasking, folders, and more. Although the Dev Team has confirmed that a jailbreak and an unlock will be released for iOS 4, it is safe to hold off on the update for a few days if you really rely on your jailbreak/unlock. iOS 4 will be compatible with the iPhone 4, iPhone 3GS, and iPhone 3G. Not all features will be compatible with all devices. For example, multitasking is available only with iPhone 4 and iPhone 3GS.