"Screen Adjuster" from the Market does much the same job, and works on ICS.
It's free, but it needs restarting after a reboot, and the changes don't show when you're in a hardware decoding video player (like MX Player).
I had an S3 for a while, and HD videos looked fabulous on it and crap on my S2. I thought it was a hardware thing, but I switched from Rockplayer to MX player (with HW decoding disabled) and jacked the red up 10% using Screen Adjuster and got the playback looking identical (only smaller, obviously)
I was happy to send the S3 back after that.