Try a google search on Simon Price, he did alot of VB for DirectX, also try http://www.dx4vb.com , it has alot of cool samples, no grayscale terrain generator though. Also planetsource code has a couple on terrain generation. If you have a specific question feel free to ask, if you are trying to learn it on your own then Best of Luck.

Dreddnafious Maelstrom

"If i saw farther, it was because I stood on the shoulders of giants."

Sir Isaac Newton