Went to the Science Museum yesterday and saw this. I had read a few years back about 3D printers but rapidly forgot it. There's a vid here on how it works.
It's interesting because it could mean that physical objects, as well as information, could be downloaded off the Internet.
Added to that manufacturing could ping back from it's location on the other side of the world to the place where it first started: the desktop.
Taking it a step further the RepRap project promises to produce a printer that can print the parts needed to build it, bestowing engineering with the fundamental biological principle of replication.
The latest on this area can be found on the Fabbaloo blog.