On a related note, here is the economist Nick Rowe's recent excellent post about what will happen if most human labor can be automated fully and cheaply at some point in the future:
http://worthwhile.typepad.com/worthwhile_canadian_initi/2011/01/robots-slaves-horses-and-malthus.html
It's by far the best and clearest analysis of the issue I've seen so far. In case anyone is interested, I left a few comments in the discussion there, which I'd say resulted in some additional insight.
My comment there:
Assume robots are the same as humans.
A situation which is very unlikely in the first place - and extremely unlikely to last for very long if it somehow magically happened. Machines already vastly exceed human capabilities in many areas.
This essay stops before things get interesting. What will politicians do if they have a big mountain of unemployed human voters to feed?
Oldie but goodie. A piece of fiction describing how a computer system can do the job of human managers at fast food restaurants (scarily plausible), how this leads to a dystopia (slowly getting implausible), and how to avoid this scenario and reach utopia (give me a break).