I haven’t ever played with cubemaps before so I set up this page to learn.
A regular texture lets you look up pixels with (x, y), or many times people call it (u, v) or (s, t). Two coordinates on a plane. A cube map texture lets you look up pixels with a direction vector (x, y, z). It finds the point on the enclosing cube, which is defined by six images.
I wanted to learn how to use them because I thought I would use them for my cube/sphere mapping. However, I ended up not using this because I found a better way to implement that. See next week’s blog entry.