  During the last couple of years, observers have started to make plans for a
Virtual Observatory, as a federation of existing data bases, connected through
levels of software that enable rapid searches, correlations, and various forms
of data mining. We propose to extend the notion of a Virtual Observatory by
adding archives of simulations, together with interactive query and
visualization capabilities, as well as ways to simulate observations of
simulations in order to compare them with observations. For this purpose, we
have already organized two small workshops, earlier in 2001, in Tucson and
Aspen. We have also provided concrete examples of theory data, designed to be
federated with a Virtual Observatory. These data stem from a project to
construct an archive for our large-scale simulations using the GRAPE-6 (a
32-Teraflops special purpose computer for stellar dynamics). We are
constructing interfaces by which remote observers can observe these
simulations. In addition, these data will enable detailed comparisons between
different simulations.
