I used the star tool and the complex star tool in Corel Draw to create this star background. It could be done in Photoshop with the shape tools, but it would be more work. I created each kind of star in Corel and exported to Photoshop where I was able to duplicate, scale, rotate and change fill color to create the variety you see here. Just keep adding layers to the bottom of the layers palette so that new layers sit behind the previous ones.
This gets a little tricky with the parts that go off the page, but you'll be able to figure that out.
This kind of background is something I am sure to use again.