I recently did a technical article on procedural noise in pixel shaders.
It discussed my procedural Cg pixel shader snippets and comes with an FX Composer project to actually play around with these.
I thought that might be of interest to some of you as well.

The URL:

I wrote those shaders as part of a terrain editor thesis project that uses the GPU not only to render but also to edit the terrain.
(If that sounds interesting, visit [decarpentier.nl/scape-render] for an project into article and a nice real-time terrain editing movie)

Kind regards,