To do it, you don't need to learn how to modify any files or mess with complicated configuration operations. All you really need to do is select a theme, and nothing more.
If you'd like to take it a step further and create your own theme, you can do that too, since Stardock Logon Studio comes with a visual theme editor.
Stardock Logon Studo only has three logon screens, but from wincustomize.com you can download many more, including some really attractive options. Click here to access the start up section.
Users of Windows Vista can download Stardock Logon Studio for free by clicking here.