Can CatchmentSIM convert from AGD66/84 to GDA94?
No. This would have added 10MB + to the CatchmentSIM download size. Accurate conversion between these datums can be accomodated by free software provided by the Intergovernmental Commitee on Surveying and Mapping at http://www.icsm.gov.au/icsm/gda/gdatm/. Furthermore a web based utility to conversion of individaul points is provided here. Commercial software, ArcGIS and MapInfo also provide support for conversion between these datums (although I am unsure if MapInfo uses the more accurate distorition grid techniques).