After reading this hint, I was going to post a comment on a better way to boot to the console, but thought it would make a better new hint rather than a comment.
By far the easiest way to have OS X boot straight to the console rather than to Aqua is to edit /etc/ttys. Near the beginning, you'll see these two lines (the second line has been split into three for easier reading here):
#console "/usr/libexec/getty std.9600" vt100 on secure
console "/System/Library/CoreServices/loginwindow.app/loginwindow"
vt100 on secure window=/System/Library/CoreServices/
WindowServer inoption="/usr/libexec/getty std.9600"
To boot into the console, you just need to uncomment (take the # sign) out from in front of the first line and then comment (put the # sign) in front of the second one. Save that file, and you'll boot into the console without editing any other files (you'll need to be root to edit and save the changes).
#!/bin/sh
/System/Library/CoreServices/loginwindow.app/loginwindow console &
/System/Library/CoreServices/WindowServer console &
I saved that as startAqua in /usr/local/bin. One needs to remember to chmod +x startAqua to be able to execute the shell script.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030716220410216