I am not too sure if this hasn't already been posted, but here is a site that provides a bunch of PSD and JPGs of various sections of the Dark Lands setting by Wizards.

http://ds.daegmorgan.net/

I thinks some people here might be able to use them. I think they are copyrighted by the creator, but I noticed that he (or she) said that you will need PS CS to use them, so (s)he seems willing to let people use them. I would suggest contacting the webmaster to clarify just what is what though.

Have fun