I was actually going to leave a comment on you work and before I knew it, it was gone. I liked your work a lot. It made me believe (that's what my father used to say). Some strokes were heavier than I would like to see, but it's just me. The only other thing i was going to suggest is to add some object(s) to it, so the whole composition would not seem monotonous and gain a sense of completeness. Why don't you re-post your work?
I know you got yourself Xara. I don't have that luxury but not so long ago I was breezing through the PS tutes and saw a sky-making tutorial. I made an adaptation to GIMP and here's what I got. It's not painting, of course and, by and large, it sucks. But painting is one of many things I can't do.
![Image](http://gimpchat.com/files/2204_Sky.png)