Skybox help....

Well, I don't know what you're planning on making it with in terms of graphics rendering, but NeHe has a tutorial (number 29, or 32, I think) that uses a skybox. You could take the code from there and modify it as you like.

A skybox is pretty much what it sounds like. It's a stationary box that has sky textures applied to the walls. The most important thing for making a nice skybox is to have high quality textures that will be applied to the walls. As far as programming one goes, check out the NeHe link above, it will certainly help.

The short of it is this: You create 5 quads (maybe 6 if you are doing the ground as well) that are not transformed when you move around the scene. This just means you render the skybox quads (or tris if you do it that way) before you do any other object rendering/transformation. The hard part is in generating or designing the textures to use.