Check out ChemFinder. A difficult site to navigate but the info is there. Chime and RasMol . Great site for modeling and visualization - by Eric Martz from the UMass Microbiology Dept. A Chemical Art Gallery .
Many links require certain plug-ins.
Most will guide you through getting those necessary. A Nice Treatment of Molecular Mechanics . Mac and Windows. ChemSketch from ACD . Literature Searching Manual and Computer-Aided Literature Searching.