You can find full specs at http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_867_dp_mdd.html.
Upgraded with 512MB memory and 80 GB hard drive. Currently running MacOS X 10.4 Tiger, but meets Apple's hardware requirements for 10.5 Leopard.
Asking $200 obo. Tower only, no keyboard, mouse, or monitor. PM or phone Gord at 613-831-1441