[SoDak]

And perhaps, actually, you can tell me, how hard is it to disable the GUI front-end?

[Swordmaker]

Look at this site:

http://www.oreilly.com/pub/h/348

I think you have to activate ROOT and initiate a password for it before attempting this.

[George W. Bush]

You can hold Command-S down while booting to enter single-user mode.

Very few Mac users even know about the root account, let alone know how to activate it.

1. Open NetInfo Manager (in /Applications/Utilities).
2. Select menu: Domain...Security...Authenticate
3. Enter the password for the account you're in right now.
4. Select menu: Domain...Security...Enable Root
5. You will be prompted to create a password for root.

Last I used it, that's how it was done. Not recommended for ordinary users, just developers and admins in Apple shops. Much of the security and stability problems in Windows is because people run as admin all the time. Running as root also enables the 'su' for root, one of the worst known security issues on any Unix-like OS so you should disable it again once you're done with it.