Steps

Step 1:Backup your iPhone, iPad or iPod touch and restore it using the iOS 5.0.1 IPSW filedownloaded above.
STEP 2: Open Redsn0w you already downloaded, select “Extras” then “Select IPSW” and browse for the iOS 5.0.1 IPSW file.

STEP 3: Now click on “Jailbreak” then “Install Cydia”.

STEP 4: You’ll need to follow the on-screen instructions to get your device into DFU mode.
STEP 5: Once done, your device will be rebooted and you’ll get a full untethered jailbreak on iOS 5.0.1.

download readsn0w 0.9.10b1 from here
[Only registered and activated users can see links. ]

its Working Good