I am recording all 22 hours of Live Earth on UniversalHD today. The satellite feed is all jacked, and it's driving me crazy.
Live Earth can also be seen on Sundance in its entirety or on CNBC (now until 11pm PDT) and MSNBC (now until 1pm PDT). NBC is also playing the concert from the US tonight from 8pm-11pm.
SIRIUS, which I have in the house, and XM, which is in my car, are both simulcasting the concerts on various channels. XM makes it easy: channels 40-46. SIRIUS is a little more complicated, so check their site for the various stations they are using for Live Earth today.