Update: The Absinthe A5 for Windows (absinthe-win-0.2.zip) has been finally released, and it is a much easier method to jailbreak your iPhone / iPad running iOS 5.0.1 than the tutorial below (which still works very well).
The Absinthe A5 is available at the time of writing only for MAC, but the last release version command line tools cinject_0.4.3.zip works on Windows as well. I prepared a tutorial (that might become obsolete once the official Windows tools are out) but still works very well if you know what you are doing. I was able to successfully jailbreak my iPad 2 using this method in about 5 minutes, and I’ll provide step by step instructions so you can jailbreak yours.
Step 0. Important!!! Set your iPad 2 / iPhone 4S as a new phone / tablet and restore firmware 5.0.1 on it. If you already started to configure it, run Settings app and select General > Reset > Erase All Content And Settings. Ensure that your iPad / iPhone is on, connected via USB to your PC and iTunes is not started. All other iTunes related process should be also stopped (Run Task Manager and make sure they are stopped). You might also need to turn off any antivirus app you have.
For this process, your iDevice should stay on the Home screen and ON. Disable screen protection and password, set to NEVER or anything more than 10 minutes
Step 1. Download the cinject 0.4.3 from the link provided
Step 2. Unzip it on the root of the hard drive. Let’s assume the drive is c:\
Step 3. For simplicity, let’s rename the folder cinject. Inside the folder you should have the content of the zip files like in the following screenshot.
Step 4. Start a command prompt windows as administrator (All Programs->Accessories->Command Prompt). Right click on Command Prompt and select Run as Administrator
Step 5. Navigate using CD command to the cinject folder. If you are in a different folder, perform a “cd c:\cinject” (no quotes) followed by Enter
Step 6. Once in the cinject folder, type
cinject.exe -i payloads/jailbreak.mobileconfig
(also no quotes) followed by Enter. Ensure that your iPad / iPhone is connected to your PC and it is on Home screen. This step will install a Profile called jailbreak on your device containing VPN settings which later will be used to inject the jailbreaking code. Watch your device screen until you are prompt for an install, accept it, leave the password field blank in the subsequent field and follow the process clicking Next until the profile installation is complete.
Step 7. Go back to the command prompt and execute the following command: (no quotes) followed by Enter
cinject.exe -j payloads
Step 8. After the previous command is complete, execute the following command in the command prompt window followed by Enter
Syep 9. Back to your device, after the previous command is executed (takes about a minute and you’ll see a lot of activity in the command prompt), change the VPN from OFF to ON. Your device should display an error dialog box followed by a auto-restart. Upon restart, you should see Cydia installed!!!
Step 10. That’s it, share your experiences to help others.