How close are we to long-term human habitation beyond low-Earth orbit? Colonies on the moon or Mars are still many years off, but the good news is there are several serious efforts underway to make it happen.
The ISS. The closest thing we currently have to a space colony is the International Space Station. While it can be considered a success in terms of international cooperation and scientific research, the ISS far from self-sufficient. Sweat and urine can be recycled into fresh water and filters and scrubbers keep the air breathable, but without regular resupply missions, the station's occupants wouldn't last long. Still, the future looks bright up there – NASA has several ISS missions scheduled for 2010, expanding the station and adding new components (as well as spare parts).