Strida folding bikes have been around for a number of years. The Strida 5.0 ($799.00 msrp) at 19.4 lbs is going to be shipping at the end of October in silver and red. The Strida folder uses a Kevlar belt, instead of the usual metal chain to connect the drivetrain. The belt is reported to last for approx. 50,000 miles. (I wrote a post in August about belt-driven full-sized non-folding single-speed bikes for 2008.)
The Strida 3.2 ($499.00 msrp) weights in at 22 lbs. Reviews of the Strida are here. (And for some reason, I seem to remember an early print ad campagin with royalty or celebs in it?)
The inventor/designer of the Strida, Mark Sanders, has also designed a full-sized bike folder, the Swivel-Head."
strida (bike site)
swissmiss (designer gal)
treehugger (alt energy site)
gizmodo (you know who they are)