At ArcGIS Desktop version 10, a new tool has been added: Delete Identical. See the link in the Related Information section below.
ArcGIS Desktop 9.x, however, does not offer a mechanism for identifying and/or removing features with duplicate geometries. Consider using one of the scripts written by various members of the user community available on ArcScripts.
Each ArcScript performs differently, so it is important to review the available options to determine the best fit for your needs. Esri does not support the content or functionality of ArcScripts, so any issue encountered with the sample should be addressed by contacting its author.