Christopher over at Playlist Mag has devised a method of booting those fancy new Intel Macs from an iPod. Power PC-based macs could be booted off Firewire compatible iPods with no problem, but apparently Intel-based macs would tell you it isn't a valid target.
Christopher's solution involves cloning a working startup volume onto the iPod, and then booting from there. Take a gander at his walkthrough in order to get your boot on.
One caveat still remains, older Power PC-based macs still can't boot off of USB based iPods. Good thing we couldn't afford upgrading!
The return of the return of iPod booting [Playlist Mag]