Pixel Bender plugin for Photoshop
The plugin is free from Adobe and I finally got it installed after weeks of dealing with a crashing Extension Manager CS4. It turned out to be a conflict with the Safari AdBlock that came with Safari 3. Upgrading to Safari 4 solves the problem. So does removing Safari AdBlock from this folder: Library/Input Managers
Anyway, once installed, the Pixel Bender plugin gives you a dozen slider-modifiable filter effects… the funhouse mirror sort of stuff we all know and love. Above, I have my head stuck into the CircleSplash effect.