However, there is one problem with watching this on the web. Flash.
This constant use of processor can often lead to the temperature of your Mac quickly increasing, as you might expect from Flash.
There is a simple solution: using the iPhone simulator that comes as part of the iPhone SDK.
By opening the SDK and going to http://live.twit.tv in Safari, you can load the video stream that's usually only available to iPhones and iPod Touches.
The iPhone stream is an mp4-encoded stream, which means it can be decoded on the graphics card. This means that you get really low CPU usage.
The only downside I've been able to find is that the stream can sometimes be a few minutes behind, which isn't critical.