How to make shadows

Hello people, i’m newbie here in this forum, and i need help to put shadows on a non-flat surface, like in a city, but i need a code or a simple example.

Can somebody help me?

Have a look at the JOGL demos. You can find two demos presenting two different way to create shadows (shadowmaps and shawdow volumes).

Or http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=27.