Source: freakgeeks.com and osxdaily.com
As we know the AirPlay mirroring was just pushed for iPad 2 on iOS 5 but some changing in the deep software can make the stuff go reverse and make it happen in all the iDevice. The steps which are mentioned below will enable the AirPlay Mirroring on all the iDevices and on iOS 4.3.3 too, but you need a jailbrokren device for that, iFunBox (Windows), CyberDuck (Mac) and a .plist editor for Mac (xCode can help you).
Follow these steps to enable AirPlay mirroring
You can enable video mirroring on the first gen iPad and iPhone 4 by using a pretty simple hack. You’ll need a few things and some patience before you get started, but it’s really not that hard to get this setup and working.
Here are the requirements:
Assuming you are now jailbroken, you must SSH into your iPad or iPhone (using the SFTP client) and locate the following directory:
/system/library/coreservices/springboard.app/
Within this directory, look for the following files: “K48AP.plist” for iPad, or “N90AP.plist” for iPhone 4
Open the appropriate file in a plist editor (requires Xcode) and add the following key, type, and value as seen in the screenshot below: display-mirroring boolean YES
Save the plist file and upload back to the iPhone or iPad, then restart the device.
Now just plug in the AV cable and start mirroring!