The most famous jailbreak software RedSn0w has been recently updated by iPhone Dev Team, providing more options for jailbreaking your iPhone, iPod or iPad.
As mentioned on the official blog the new version of redsn0w 0.9.12b2 will explicitly ask the users with Limera1n enabled devices whether they want to inject rocku-racoon or not. Similarly the new version also fixes an issue with iBooks on old bootrom 3gs iphones.
Below I have given links to download RedSn0w and how to jailbreak 5.1.1 using RedSn0w.
Below is as mentioned on official blog.
Starting with version 0.9.12b2, redsn0w will now explicitly ask users with limera1n-able devices whether they want to inject rocky-racoon using the DFU ramdisk method or the backup/restore method (the ramdisk method is better for those with lots of media on their device that would create very large backups, and it’s required for those with unactivated iPhones). If you’ll always want to use limera1n, you can select that in the Preferences pane. It also fixes an iBooks issue on old-bootrom 3GS iPhones, and provides more useful error messages when things go wrong.
If you want to jailbreak your iphone 4, iphone 4s, iphone 3gs, ipad 3, ipad 2, ipad 1, ipod touch 3g, ipod touch 4g or Apple TV you can use below tutorial on how to jailbreak 5.1.1 untethered using RedSn0w 0.9.12b2. Below are also given download links for jailbreak software.