Which EPSG code relates to the projection of my shapefile data?
The below linked website can help with determining which ESRI projections relate to which ESPG codes.
Simply browse to your shapefiles *.prj file, select convert, and the site returns EPSG code(s) and details which match your shapefile projection parameters.
In addition, the below linked EPSG Geodetic Parameter Registry website contains functionality to query EPSG codes by name.
