Via Doc Searls' closing comments on the sad Columbia events I found a host of stuff about Space elevators. Such a really great idea, I've been idlely thinking around writing a novel/short story/film script over the past few years about this topic.
Essentially, build a strong cable to geostationary orbit and then run cars up and down it at a fraction of the cost of sending rockets into space. Also as Dana Blankenhorn notes there is a scaleability here, as once you build once then you have the facilities to build another and you can use the first one to put everything into orbit to create the second, third and fouth. location of the ground station is a concern as it will be a very vurnerable target, however if you have more than 2 then you can have redundancy. For lots more detail on this topic have a look at the conference presentations from the space elevator 2002 conference hosted by HighLift systems.
The Radio 4 programme, The Material World 5/dec/2002, has an interesting radio interview about space elevators, RealAudio file interview starts about 15 minutes in.
The end of Dana's article makes it sounds achiveable, at least within the next 20 years, certainly the costs are less than we'll spend on the coming war with Iraq
Carbon nanotubes are the key technology for a space elevator. This is a single molecule of carbon, one that starts as a sphere (a "Buckyball") but is designed to extend outward (in theory, infinitely) in two directions, forming a tube.
The problem with nanotubes has been they cost so much to make, but there have been some great innovations in that area over the last two years. Watch how fast production ramps-up for such things as tennis rackets, bicycle frames and such, as early as this year. Then watch the production costs drop.