From the Earthship website at http://www.earthship.org/ :
Earth - Ship n. 1. passive solar home made of natural and recycled materials 2. thermal mass construction for temperature stabilization. 3. renewable energy & integrated water systems make the Earthship an off-grid home with little to no utility bills.
EarthShips are a form of home architecture, often designed into a hillside, which utilize the thermal mass of the earth itself to keep the house cool in summer and warm in winter. There is a lot of info and many photos on the main earthship website, and you can even rent an earthship for a few nights or a week of vacation to try it out firsthand! (The earthships pictured on this page are available for vacation rentals.)
EarthShips are built to be in tune with their local environment, rather than simply plopped down in a subdivision-sector like so many houses in suburbia. They utilize and generate their own energy (often completely, as they're popular in remote locations with no grid connectivity) and recycle their wastes using systems like Living Machines.
EarthShips are a fine example of Autonomous Houses, although they lack the mobility aspect that some autonomous house designs attempt to implement.
There are also numerous books on EarthShips, which we should list here. (Hint Hint!) For now, check out http://www.earthship.org/market/books_videos.php for a great list of resources for learning more.
Please add more links and info to this page.