You can explore any 3D macromolecular structure model (PDB file) in either: Protein Explorer in Chime (Current Version) Best for beginners (lots of help), yet powerful for advanced users. Works only in Windows (including Intel Mac OSX with Parallels.Com) and Mac PPC OS9/Classic. Must install the free MDL Chime browser plugin. Make custom views with complete control over the molecular view. Undo. Create MolSlides. Save/restore earlier sessions. FirstGlance in Jmol Assumes that you are familiar with the principles of protein structure, and with finding PDB codes. Nothing needs to be installed (except java). Works in popular browsers in Windows, OSX, and linux. Relatively simple. Most molecular views are pre-determined. Supports user-defined views of non-covalent contacts, but not other custom views. Older versions of Protein Explorer Other free molecular visualization software packages are listed at MolVisIndex.Org. Educational molecular visualization resources for teachers: MolviZ.Org For high school (secondary school) biology teachers: BioMolecular Explorer 3D