Custom Skyboxes

[JenniferOrange]

I'm a little (frustrated) curious to know how one goes about making their own custom skybox. You know, taking a picture of a sky and cutting it up so it works. It's gotten harder to get skyboxes now that cgtextures has moved and now charges money. I'm not paying for that. Is there some kind of template or instructions on how to do this? I'm running Adobe Photoshop CS5, and I have the .DDS plugin. I've tried changing the size and making a 'cube map sky' into a dds but it doesn't show in the editor. D:<
Some of you may suggest that video game pack I forget the name of, that has all the nice textures, but there is no way in hell I'm downloading a giant package just to fish out some sky textures. c: