And installation is a breeze. There's nothing to configure in command line; it's all drag and drop.
1) Download the theme that you want to use from the GNOME Art library.
2) Open the
Login Windowmanager. That's
System->Administration->Login Window. You'll be prompted for the administrative password.
3) Click on the
4) Drag-and-drop the newly downloaded theme package into the themes selection box.
And that's it!