3d Background

Try searching for skyboxes.

There are plenty of tutorials/articles on skyboxes. Basicly, my way is to draw a quad in the distance that moves with the camera. Also draw the four directions and possibly the sky and bottom, if you can look up and down as well. The trick is that the textures need to be seamless at the sides so you can't tell from a distance that they are quads. If done right, you can't tell the difference.