These I did mostly this last month. I tend to do 1-2 a day, but these days life has been busy, so I'm falling behind!
These would make cool posters/wall art, if you have a good commercial printer and high resolution Photoshop files. You probably could get some commission work - maybe work with a professional photographer to make montages of their models.
I like the second picture very much. Can you tell me how to do so, I am interested in that.
I use Photoshop CS3 for all my work. There's a lot that goes into this whole thing, but if you go to the-dark-arts.net, and go to the tutorials, you'll learn a lot. That's what I did, and it really made a difference. YouTube has a lot of PS tutorials, too, so that's another source.
Are you on deviantart.com? You could sell these and get commissions from people. My DH found the cover artist for his recent album on deviantart and I browse there every so often to find good illustrators.
These are really excellent. I work on Photoshop too and can appreciate how much skill has gone into these. (I would never be able to reproduce this sort of thing!!)