Lo puedes hacer con la herramienta Split Features, o Split Layer By Attributes (script)
http://www.umesc.usgs.gov/management/dss/split_by_attribute_tool.html
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//000800000006000000.htm
http://www.arcgis.com/home/item.html?id=15ca63aebb4647a4b07bc94f3d051da5