Reselling my iMac in updated, but "out of the box" condition
I am going to be selling my G5 iMac soon, and as a courtesy to the buyer (and also to help entice said buyer) I'd like to say I'll be selling the computer with the latest version of OS X (10.5.6) already installed on the machine. But I'd also like the buyer to be greeted with the Setup Assistant as soon as they turn the machine on, as though they had just bought it new. Is this process possible? If so, how do I do it? I'm not afraid of mucking around in the terminal if needed, but in that case I'll need very detailed instructions.