Launch is now set for 2am EDT / 11pm PDT / 6am UTC
'Hosted' (lots of talk) Webcast: https://www.youtube.com/watch?v=lZmqbL-hz7U (the countdown you see is until launch, not the start of the stream!)
'Technical' (minimum talk) Webcast: https://www.youtube.com/watch?v=zl8mi7laQGk
Twitter updates: https://twitter.com/SpaceX
This launch is of a communications satellite to GTO. Due to the mass of the satellite (5.6mt), no attempt will be made to land the booster. (The heaviest previous landings were JCSAT-14 @ 4.7mt and JCSAT-16 @ 4.6mt.)