CambridgeSoft Corporation,
formerly Cambridge Scientific Computing, provides free demonstration
versions of their commercial programs
ChemDraw & Chem3D.
They provide versions for Windows, MacIntosh, and unix. ChemDraw provides
sophisticated drawing tools for 2D chemical structures. Chem3D displays
molecules in 3D (optional stereo), with rotation and various representation
options.
Moreover, CambridgeSoft provides a database of 2,500 micromolecules which can be searched at no cost with their utility ChemFinder, from the web.
The resulting structure files can be displayed by ChemDraw or Chem3D, but are in a proprietary format which can't be displayed by RasMol. However, with the free version of ChemDraw, you can convert a ChemFinder structure to SMILES format. You can then submit the SMILES formula to CORINA, which will return a PDB file viewable in RasMol.