I am looking in to using a old G3(about 8GB RAM but i only need 1-2)for a minecraft server.

I need too conserve power and I am looking for a free OS that has java and doesn't use much power...option to auto shut down at night and start in the mourning would be very useful.

Ohh, and i need to be able to VNC or the like from my new(10.7(yes, the beta))intel mac laptop.