Excellent job! I’m working on perfecting a night sky for a video I’m making and it is not easy.
Personally, I think a starfield is about the toughest thing to create on a computer. Computers just don’t do random very well.
BTW a great starfield tutorial here (as well as some other good space themed tuts.)
http://naldzgraphics.net/tutorials/30-photoshop-tutorials-for-creating-space-and-planets/