SIM PlanetQuest will investigate, using stellar interferometry from space, a broad range of topics in astronomy and astrophysics. Chief among its scientific goals is a search of nearby stars for terrestrial planets in the circumstellar habitable zone. Composed of three astrometric interferometers each capable of resolving approximately one billionth of a degree, SIM is poised to revolutionize our understanding of the Universe in a number of areas. With the completion of its technology development phase, SIM is now on a sure footing for the development of requirements for the flight instrument. The preliminary design of SIM is in place and many key brassboards have been built. Here we review the project status and recent progress.