Hey TheVestel I'm sorry I don't have PS with my PC right now but I thing you can achieve it by changing Shadow/Highlights and a bit of Brightness/Contrast adjust If you want the sky colour to be changed, you can do some Color adjustment or variation 
Sorry for not being more helpful
Message edited by Neil on 11-12-2008 at 08:38:06 AM
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I'm not an agent but a fan of Crystal XP