If you're on stock iOS 5.0.1 please use this method
1: Download Redsn0w from one of the links below
Redsn0w 0.9.10b1 for Windows
Redsn0w 0.9.10b1 for Mac
2: After downloading Redsn0w it will be compressed into a zip file. Extract the file to your PC or Mac and then run RedSn0w. Select "Jailbreak" and then put a check where it says "Install Cydia". And follow the steps on the screen to start your jailbreak.
After it has completed go to open up Cydia to make sure it is working. Enjoy! :) If you're on a tethered iOS 5.0.1 jailbreak please use this method
1: Open up Cydia and download Corona 5.0.1 Untether which is a package developed by Chronic-dev team
2: Reboot your device. And enjoy the untethered jailbreak :)