ArgusLab is perfect for calculations on dye molecules using ZINDO and SCRF.
It runs on Windows, performs Zindo calculations and has a very nice interface to Zerner's SCRF method with automatic calculation of solute cavity radius and a series of common solvents to choose from (or you can type in your own solvent parameters).
Furthermore, it has a great molecule builder and surface rendering capability.
You can make terrific surfaces showing, for example, the enhancement of the shift in electron density, electrostatic potential, etc, from the ground to excited states comparing SCRF calculations with gas-phase calculations.
I've put some sample surfaces on the website at the Planaria image gallery (http://www.planaria-software.com/gallery.htm)
You can obtain version 2.0 and version 3.0 beta from http://www.planaria-software.com