Enabling root user in Leopard
1. From the Finder's Go menu, choose Utilities.
2. Open Directory Utility.
3. Click the lock in the Directory Utility window.
4. Enter an administrator account name and password, then click OK.
5. Choose Enable Root User from the Edit menu
6. Enter the root password you wish to use in both the Password and Verify fields, then click OK.
And there you go, we now have root access.