It's a fancy name for Corrugated Iron. Basically it is sheets of painted steel. It comes in various profiles, the most common of which is called Custom Orb ... don't ask me why ... it's the format most people would know as galvanised iron, or tin shed.
Colorbond is usually used as a roofing material, in the country people build sheds from it. But today more and more archetects are using it to create a new look building.
Colorbond is made by BlueScope Steel or whatever they are calling themselves these days, previously known as BHP. Unfortunately there is not a lot of competition in this area to drive down prices.