Earthsculptor is the current project I'm working on. It initially started as a terrain engine, now it's a tool for editing generic heightmaps faster than anything currently out there now.

www.earthsculptor.com

PNG Win32 programming guide

A series of pics of some of my work with vertex/pixel shaders on Raze's Hell over at Artech Studios a few years ago

Blooming and Heat Shimmer Fire (DivX 500KB)

Shadow mapping with vertex shaders to fade out the shadow by distance

Blooming the sun

Weird distortion and channel swapping