ZBrushCore provides a simplified version of Decimation Master to optimize your model for 3D Printing. This is needed to reduce the number of polygons without affecting the model quality. Choose from the presets in the Zplugin>Decimation Master sub-palette.
You can then use the 3D Print Hub (also in the Zplugin palette) to export your model in the format you want ready for uploading to Shapeways, Sculpteo, iMaterialize and many more. You can of course also export to your own 3D printer.
Read more about the 3D Print Hub here.