While iOS 5 is already jailbroken on a number of devices like iPhone 4, iPhone 3GS, iPad and iPod touch, an iPhone 4S jailbreak is, unfortunately, still some time away.
Jailbreaking gives you a way to install software on your Apple device that originates from somewhere outside the company's App Store universe, without Apple's seal of approval. It also enables users to make unauthorized tweaks to the device's mobile operating system. Jailbreaking voids the user's warranty and could cause damage to the user's device if not done properly.
After the release of iOS 5, an untethered jailbreak and unlock for iPhone 4, called FastRa1n 0.5 for iOS 5, has been claimed to be released by FastUnlockiPhone.com. As soon as iOS 5 came out, some jailbreak developers released a tethered jailbreak version for various iPhones, the iPad 1 and several iPods. A tethered jailbreak means that if you install it, it will only stay active until the next time you reboot the device. Therefore, once you reboot the device, you will need to redo the jailbreak. So jailbreakers have created an untethered jailbreak solution for those devices.
Now the dev-team is working on a jailbreak for iPhone 4S. Reportedly they have a lead on jailbreaking the iPhone 4S and the iPad 2. These two devices are proving more of a challenge due to the new A5 processor, but progress is on.
As per a twitter message from Musclenerd, the well-known iPhone hacker, “Not too surprising, but can now confirm that the iPad2 and iPhone4S bootrom are the same version iBoot-838.3.”
As of now we will wait for an iPhone 4S jailbreak to arrive.