Justin.tv announced that they now officially supports DVD quality broadcasting using the h264 video codec - and it even works on a Mac!
The video looks crisp and plays smoothly, which really makes watching live video an enjoyable experience. Take a look at the 4PlayerPodcast channel or The Officecam (pardon our mess!) to see examples of how good it can look.
To get started with your own h264 broadcast on a PC, follow The Windows Guide. Mac users should use The Mac Guide instead. If you're new to broadcasting with h264, you might want to read this Overview to see what it's all about.
Justin.tv doesn't record h264 broadcasts at this time, so if it's something you want to hang on to, don't use h264. This will be coming soon.