Think Of Penguins GDM Theme
This is not my original work. I took the ArchDark GDM Theme, changed color, and added new background. :) Almost all of the XML coding as well as design for the "log in" part was done by the authors of the original ArchDark GDM.
ArchDark 0.2 - http://www.gnome-look.org/content/show.php/ArchDark?content=94030
Visit my profile page to see other GDM themes and other artwork.