iPhone 5 jailbreak should be pretty easy
At today's MyGreatFest jailbreaking convention, master hacker P0sixninja announced that a jailbreak should be coming pretty quickly to the iPhone 5, in a far shorter amount of time than was necessary for the iPad 2 jailbreak. The good news is all thanks to the Chronic Dev Team, which has found 5 bootrom exploits in the A5 chip which powers both the iPad 2 and the iPhone 5.
A reliable jailbreak proved hard to come by with the A5 and the iPad 2, because the bootrom is found inside the A5 chip and required a lot of hard work to reverse-engineer and find the exploits. That's why it ended up taking about 4 months to find a reliable jailbreak for the iPad 2. However, since then, the Chronic Dev Team has found 5 userland bootrom exploits. A userland exploit means that it is software-based, which means that even a hardware revision won't do anything to derail this jailbreak.
You may remember that iOS 5 was jailbroken just hours after the announcement at WWDC, so the only worry had been in the iPhone 5 hardware, but now it seems that won't be an issue either. Now, we just need to wait for the iPhone 5 to be released.
source: Redmond Pie