Coming out in March, 2012. http://news.cnet.com/8301-17938_105-20108986-1/revolights-ditch-your-bike-lights-for-wheel-leds/?tag=cnetRiver Check out the picture at the bottom of the article. $220 
I don't ride as much as I used to (read: rarely nowadays), but if I did, I would definitely get a set of those to be seen. Those look soo cool! Kinda like "light cycles" from Tron.
Basically, each LED projects forward, across the tire's sidewall. Sort of like when you take beamshots of lights laying on carpet, the LEDs mounted on the rim light up the side of the tire. And since light leaves a "trail" at night, it looks like the whole section of tire is lit up. I wonder if you could program it to light up the entire tire? That would be TRONerrific! 
But I have to disagree that it will be enough light to actually "see" and not just be "seen". You will definitely need a headlight. That said, this will be the first wheel-LED that projects light forward as well sideways I believe.
Here's a video. I like how the guy is on the wrong side of the road in the demonstration. 
