Universal Sports, broadcasters of the UCI Cycling World Championships and some other races, will not require the Microsoft Silverlight plugin that (probably) prevented a large number of viewers from watching the Olympic cycling events. Although Universal Sports is a joint venture with NBC, along with WCSN, they have so far decided not to copy the NBCOlympics.com video streaming setup.
Presently, the Universal Sports homepage has a number of videos you can test out. I tried and couldn't get the video content loaded... so we're not in the clear yet. But I've been told they're still working out the bugs, so no worries yet. At least the player loads instantly, and looks nice and large. I'll keep you posted on more info, and hope to have a full list of system requirements to post as we draw closer to the Worlds. I'm sure, like any new stream source, it probably won't work on every machine, but unlike NBCOlympics.com they seem intent on making it as easy as possible to get on.
update: Among those other races they're showing are the Deutschland Tour.