  The Virgo Cluster is the dominant mass concentration in the Local
Supercluster and the largest collection of elliptical and lenticular galaxies
in the nearby universe. In this paper, we present an introduction to the ACS
Virgo Cluster Survey: a program to image, in the F475W and F850LP bandpasses
(Sloan g and z), 100 early-type galaxies in the Virgo Cluster using the
Advanced Camera for Surveys on the Hubble Space Telescope. We describe the
selection of the program galaxies and their ensemble properties, the choice of
filters, the field placement and orientation, the limiting magnitudes of the
survey, coordinated parallel observations of 100 "intergalactic" fields with
WFPC2, and supporting ground-based spectroscopic observations of the program
galaxies. In terms of depth, spatial resolution, sample size and homogeneity,
this represents the most comprehensive imaging survey to date of early-type
galaxies in a cluster environment. We briefly describe the main scientific
goals of the survey which include the measurement of luminosities,
metallicities, ages, and structural parameters for the many thousands of
globular clusters associated with these galaxies, a high-resolution isophotal
analysis of galaxies spanning a factor of ~ 450 in luminosity and sharing a
common environment, the measurement of accurate distances for the full sample
of galaxies using the method of surface brightness fluctuations, and a
determination of the three-dimensional structure of Virgo itself.
