Moving Through Walls

I am completely new to game programming and i am very confused on how to implement a collision detection system to stop me walking through a wall …

I started off with the code from http://nehe.gamedev.net OpenGL Lesson 10

I understand how the 3D enviroment is created but i would much appriciate any help on how i could stop the camera moving thru the walls ?

Thanks - Martin

Try out www.gametutorials.com. The opengl section there contains some tutorials on collision detection and also to detect the collision of the camera with the world. It should help u out.