Pod2g has confirmed that his untethered jailbreak is working for the iPad 1 and iPad 2 on iOS 5.1.1.
iPad1,1 and iPad2,1 tested with iOS 5.1.1. Untethering worked.
That means the list of confirmed working devices now includes: iPad 1, iPad 2, iPad 3, iPhone 4, and the iPhone 4S. Unfortunately, it was revealed earlier today that the iPod 3G and iPhone 3GS are not vulnerable to the kernel exploit used for untether. Hopefully these devices will still be able to use a tethered jailbreak.
It's still unclear when pod2g plans to release his jailbreak for iOS 5.1.1; however, he did hint that it may be during HITB SecConf Amsterdam.