This microscope is a project by Sacha De’Angeli of ChemHacker.
STM system is a non-optical, high-resolution, microscopy technique that is often used to obtain images of a conductive surface at the atomic scale. A sharp metal tip is placed only a few nano-meters from surface, a current is applied between the two (Tunneling Current). The amount of current produced is exponentially dependent on the distance between the tip and the surface. Scanned points relative to the Z-position of the tunneling tip will produce a topographical image of the sample surface. If the resolution is high enough, the resulting image will show individual atoms.
Sounds like kits will be going on sale, you can sign up for news at the link above. [Via element14]