Ac1dSn0w is a new tool designed to jailbreak devices on iOS 5. Currently, as you may expect, it doesn’t work on the iPad 2 and the iPhone 4S. It’s also a tethered jb. The advantage to this tool is that it’s much easier to pull off than many of the other jailbreaks currently available.
Ac1dSn0w currently works on the following devices: iPhone 4, iPhone 3GS, iPod touch 4G, iPod touch 3G and the first-gen iPad.
1) Download Ac1dSn0w for Mac: Link
2) Launch the application and you will get a window with the following options: Jailbreak, Tethered Boot, Pwned DFU, Exit Recovery.
3) Connect your iOS device to your computer via USB and power it off.
4) Set your device to DFU mode. This can be done more easily with Ac1dSn0w’s built-in assistant.
5) The device will go into DFU mode. Hit the Jailbreak button within Ac1dSn0w.
6) When you need to reboot your device at anytime, you will need to reconnect to Ac1dSn0w and use the “Tethered Boot” option to boot your device.