What a bright idea:
If researchers at Boston University's College of Engineering have their way, light bulbs of the future may be the highway your data gets carried along. A team at the school is working on low-power LEDs which could utilize an optical communication system to carry data wirelessly.Read more about this here.
Using a technique which rapidly switches the LEDs on and off data transmissions could be made via imperceptible -- yet undoubtedly brain-scrambling -- flickering patterns, and each light would be its own network entry point at speeds of 1 to 10Mbps. The concept is more secure than current RF techniques because it requires linked devices be in line-of-sight, and the technology would draw far less energy than conventional radios.
P.S. -- Two difficulties I see with this technology are:
1) It requires lights to be on. (Although maybe some form of infrared or ultraviolet could alleviate this.)
2) It requires line-of-sight transmission between the computer and light emitter, rather than uni-directional like a radio wave. This could constrain placement of devices and could create problems of people getting in the way of the transmission and constrain where laptops could be used.
I'm sure the technology could be developed (and maybe already has) to mitigate most of these issues. With all that being said, this technology is still pretty cool.