Now press the "switch cameras" icon in the upper right corner of the iPhone's Camera app so that the FaceTime camera's view is being displayed on the screen. You will probably see yourself on the screen.
Now point the FaceTime camera at the LED end of your TV remote control and press a button on the remote.
Your eye can't see the IR light, but now you will see the IR light appear in the viewfinder as a bright white light.
It turns out that the FaceTime camera on an iPhone 4 does NOT have IR filtering on it! Yay!
I hope this is useful to even just one person in the Instructables community. Please use this information for good, and not for evil.