Absinthe 2.0 is the untethered jailbreaking tool for latest iOS version 5.1.1. Greenpois0n will be release Absinthe 2.0 recently and most new iDevices users will be satisfied with this version.
Absinthe 2.0 untethered jailbreak supported devices
This will be support following most of the devices without AppleTV 3
Support devices are iPhone 4S, iPhone 4,iPhone CDMA, iPhone 3GS, iPad 3 WiFi, iPad 3 Global, iPad 2 WiFi R2, iPad 2 WiFi,  iPad 2 CDMA, iPad 2 GSM, iPad 1
@pod2g said this is working well for iOS 5.1.1. This tool similar with A5 5.0.1 jailbreak. Click here to see @MuscleNerd note about this tool. Absinthe 2.0 newly release tool will install Cydia directly and also not need to set DFU mode. @MuscleNerd mentioned information tentative and may be refinements. Following Youtube video for new release Absinthe 2.0.