Premiumbeat has a cool tutorial on how to replace screens with graphics or video in After Effects.
The screen replacement effect is created by tracking live video using the tools that come packaged with After Effects (no third party filters or plugins required). Highlights of the tutorial include:
Using the Warp Stabilizer to smooth camera motion
Using the Perspective Corner Pin Tracker to isolate the device’s screen
‘Selling’ the effect by applying screen glow, beveled border and simulated light streaks
Here’s the tutorial:
To read the transcript, click here.