AFAIK the skyboxes are just normal images that you can modify in Photoshop and the like. They should all be .tgas in the Textures folder somewhere.

Actually they are .dds textures, not .tga. But yes, you can edit them in any image editing program which can work with .dds format images.

There are two types of images associated with skyboxes; environments and backdrops. Backdrops provide visual stuff - what you see in game. Environment images provide lighting tint, so that objects such as ships, planets and structures reflect correct environment and thus blend into the setting better.

One thing to keep in mind is, you need to be able to work around the seams which will pop up because backdrop imagery is mapped to a sphere with flat polar caps (not the usual spherical mapping which stretches polar texturing). Second issue is image quality - I recommend using Nvidia's Texture Tools 2 because they give a better compression quality than what you get from their Photoshop plugin. Since the backdrop images get stretched over a relatively large surface, you need to keep the image as high quality as possible and still in acceptable resolution.

Thank you very very much Manshooter, i appreciate it. Im brand new at this, haha, so i will probably have to read everything i can get my  hands on, and fail alot, until i can figure out how to do this even partially acceptabley. But i appreciate the help and the pointers. Take care and i'll let you know how it goes, haha, probably you wont want to hear me complain, so it may be awhile before you hear anything positive.   But thanks again.

-Teal