Search for "composite", that should give you better results
X.org from 6.8.1 onwards has the XComposite extension which allows things like shadows, real translucency and other eye candy stuff. It's pretty hard on your graphics card do you mightn't like it once you get it working though but different people get different results. In 6.8 it's been very iffy and not exactly stable. The situation has improved dramatically in X.org 7 but I don't think many distros have updated to that yet.