In here you'll hopefully soon be able to find tutorials about all aspects of modeling, texturing and opting. Together with some other stuff, too.!
For now Decoy made the beginning with his Texturing Tutorial which sure is something you should check out!
In Addition to that he also made a Machinery Texturing Tutorial, which is very nice if you want to add some extra detail to your craft!
Wow, after a couple of years without any updates there is in fact a new tutorial! The Guide to Atmospheric Backdrops by frakel!