The Sheffield Chemputer is a site that does a variety of calculations including: isotope patterns, element percentages, reaction yields, oxidation states (for transition metal complexes), electron accounting (for metal complexes), VSEPR shape and classification using the CBC method. At the initial point of this post (April 29, 2014) parts of the site are still under development, but it seems to be off to a good start. It is capable of processing some simple ligands (ethylenediamine, En, for example), but it is a little fussy in terms of entering ligands (En must be En not en) and after doing a calculation you must hit think link to return to the jump off point of the calculation. Once these little bugs are worked out, this could prove to be a valuable resource.