Here is the galaxy tutorial I promised some time ago. I hope it will help you creating some nice galaxies.
Please show me your work if you tried out this tut so I can give you feedback.
You can check the final result of this tutorial here: [link]
And heres another example for the result with the same techniques: [link]
Another good example by ~R3V4N
I merged the multiple PDF's into one file and compressed as ZIP.