I was just reading this piece on Live Earth. I started watching the C4 broadcast time-shifted on Vista Media Center over the weekend. I still got frustrated by the constant ad's that were the same every 10 or 15 minutes (crunchie or smokefree anyone?) and also I got the feed through Sky from C4 and although it was broadcast in widescreen HD internationally I got a cropped letterbox picture that appeared to have been made analog and then back to digital :(
I tried the live stream at http://liveearth.msn.com but I was a bit frustrated by picture quality when I scaled to fit full screen on my TV although the sound quality and consistency of the stream was excellent (It's a shame that Silverlight and LiveStation wasn't ready in time), 10 million active live streams would have been a great test for p2p!
That said there is a great collection of videos available ondemand from the concerts, my favourites Crowded House, Smashing Pumpkins, Chris Cornell, David Gray, Jack Johnson and of course Yusuf.