Scientific results are now being produced by the first 42 antennas of the Allen Telescope Array (ATA). The array is being built at the Hat Creek Radio Observatory in northern California by the SETI Institute and the University of California Berkeley Radio Astronomy Laboratory. This revolutionary array will eventually consist of 350 dishes, each 6m in diameter, and will be an ideal instrument for surveying the radio sky for astrophysical sources and signals from distant technologies. It will have the collecting area of a single telescope 114m in diameter, the spatial resolution of a 900m diameter antenna, and unprecedented instantaneous frequency coverage from 500 MHz to 11 GHz. The array makes use of COTS technologies to minimize cost, and its design enables SETI and traditional radio astronomy to be conducted simultaneously.