If you login with the username >console with no password you will bypass the Aqua interface and be presented with a text login screen. I came across this hint at daemonnews.org. I hadn't seen it here and so I thought I would share the info.
[Editor's note: Simply typing logout will return you to the GUI login screen.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20001206013058169