Until now, there was no untethered jailbreak for the iPhone 4S and the iPad 2 with iOS 5 and 5.0.1 respectively. After a restart of the device, the jailbreak had to be performed again each time. Now there is a tool called Absinthe (message on PCGames.com), which performs the jailbreak under MacOS. An integration into the well-known redsn0w tool is planned, as well as a Windows and Linux version.
The jailbreak is supported on iPhone 4S with iOS 5.0 (build 9A334) and iOS 5.0.1 (build 9A405 and 9A406) as well as iPad 2 with iOS 5.0.1 (build 9A405). The application is very simple: Download Absinthe (either from Greenpois0n or pod2g), start it with iPhone or iPad connected and press the corresponding button. If something doesn't work right away restart the device and try again - of course there is always a risk that jailbreaks that are not provided by the manufacturer might damage the device or not work as desired.