I tried my hand at this a while back (using Gimp). I used a Sparks brush with the paintbrush tool at a relatively low opacity to paint in the city lights. I can't actually find the original picture but I'll post it if I come across it.
I like how yours is coming out kridenow. I will be watching with interest.
Well, I moved to another office and went from Photoshop CS3 to an older version.
And the .psd file doesn't open correctly (all layers are fused into one).
So I guess the work on this will have to wait until I find a way to get back all my layers :)
(as well as the world map of the planet Andoria from Star Trek I just started to work on...)
I was considering darkening a bit more the shadowy region and lessen the stars brightness (and remove the brightest, large, one at the bottom).
Save each layer as a png, or something like that which supports transparency, and then put it on a disk or email it to yourself. When you open the new layer in the older version the transparency might still be there but if not it'll probably be a solid color that you can easily delete. Also, write down if the layer has a blend mode.
That probably woul d be what I should do... however.... accessing my former office place is a tad... difficult :)
So I guess this work is lost anyway, unfortunately.
And time to restart my map of Andoria (I'll post early work soon I hope)
Very nice, but you should add some lights further inland.