This is a good page for the basics of STM, or maybe you want something a bit more in depth. If you're really a geek, check out some STM theory.
The first paper about Nanocars published in Nanoletters
My Master's work consisted of characterizing and manipulating a new molecule called the Nanocar, synthesized by the Tour Group at Rice University in Houston, TX. These little (~3nm - really little) molecules are quite simple conceptually, but represent what I think is one of the first real forays into the nascent future of nanomachines. With four fullerene wheels (C60) that rotate freely around the axles, the molecule moves on a surface (Au(111) in most cases so far) by means of the rotation of the wheels. This doesn't seem like a big deal until you realize that the traditional idea of friction doesn't exist at this level, and that individual atoms of the surface represent a significant hurdle to these tiny molecules. What's more, these molecules were designed specifically to do exactly what they do, and represent the first successful molecule purposefully designed and synthesized specifically for nanoscale manipulation and transport.