According to this very interesting article, Since transistors where developed in the 50's they've shrunk from being fractions of an inch across to today's 50 nanometres across - which is akin to shrinking the US down to the size of a hot-tub. Now researchers have taken another step forward in miniaturisation - they've worked out how to make individual molecules act as transistors:
Scientists at the University of Arizona have discovered how to use quantum mechanics to turn molecules into working transistors in the lab, a breakthrough that might one day lead to high-powered computers the size of a postage stamp.
Results of the as-yet-unpublished study came together just weeks before Canadian researchers performed a similar feat using chemical means. That experiment appeared in the journal Nature last week. Together, the two studies could bring the final frontier in nanocomputing -- a single-molecule transistor -- considerably closer to reality.
The transistor -- the essential building block of computers -- is a circuit component that amplifies or halts an electrical signal using three leads: The first two leads are like two ends of a garden hose; the third is like a valve that regulates the flow of water through the hose.
More from Wired here
Wow - today's chips have unbelievable amounts of transistors on them... If this plays out, just think how many you'd get on an average sized die. Of course, it's still a way out, and I'm sure there'll be other obstacles to overcome (When things get this tiny all sorts of odd stuff happens if I recall correctly), but I for one can't wait to have my own 'Blue Gene' in my wrist watch...