wireless transmission of power?

I've heard of some proposals in various places that could beam energy from space into large dish receivers on Earth, which could transmit power without needing to burn fossil fuels or use a nuclear reactor. Like microwave, or something (I'm thinking SimCity 2000). First, is that possible? Second, how would it work (if it is possible)? Third, is it feasible with today's technology? Fourth, would it be economical?