Creating partition for Diskwarrior
A couple of options:

1)  Use an external DVD drive connected via USB to boot into the Disk Warrior DVD

I use a spare IDE DVD-R drive from an old PC connected with a Newer Tech USB to IDE adapter.  I have had to do this a few times with a Mac Mini Server.  The only problem is that booting this way is VERY slow.

2)  If you have access to another Mac, connect the problem machine to the good mac with a Firewire cable and boot the damaged machine holding down the "T" key to enter Firewire Target Disk Mode

http://support.apple.com/kb/HT1533?viewlocale=en_US&amp;locale=en_US

Then run Disk Warrior from the good Mac on the problem Mac's drive.

For the future:  These are better options but probably not as easy at this point.

I try to have a USB flash drive around with a clone (via Carbon Copy Cloner) of a working system that contains the emergency utilities like Disk Warrior.  I can then boot from it if needed.

I also like keeping a bootable clone on an external hard drive with Disk Warrior already installed as part of my backup strategy.

You can select an alternate boot volume when turning on the machine by holding down the &lt;option&gt; key.