After Sky box/Terrain Tutorials... nub request

I’ve followed several terrain tutorials like this one at blenderwiki - - and some skydome/box tutorials, but they all end with the making of the sky box mesh/ the terrain mesh & textures. My question is: how do I get the skybox/terrain to actually do anything? Can I simply scale both up to be actual size? In several tutorials they said to put the camera inside the skybox, but then can I link that to another camera and make the sky image the background for a real scene?
So that was a lot of questions, but I hope they aren’t too hard to answer.