GABEDIT is a Graphical User Interface for Computational Chemistry

 
GABEDIT is free and can be downloaded.

Install Gabedit - installation instructions can be found here.

For instructions on how to visualize complexes, go to Viewing molecules.

To draw a complex and prepare MOPAC2009 input files, go to Drawing Complexes.

Study the Tutorial on how to use GABEDIT with MOPAC2009.