UPDATE: They did it!!
For those of you awake right now, Spacex's Falcon 9 rocket with Dragon capsule will be launching from Cape Canaveral, Florida in less than an hour. If successful, this mission will see the first private spacecraft docking at the ISS. Check out the webcast and live text/video updates from SpaceFlightNow:
Dragon won't be docking with the ISS until Friday so don't wait up for it tonight. You'll see the Falcon 9 launch, taking just under 10 minutes to reach orbit at which point Dragon will separate from the second stage of the rocket. Depending on video Tx range, we may also get to see the solar arrays deploying (even the big guys have trouble with FPV!) After the video cuts out there should be a press conference discussing what happened and explaining any anomalies.
As a former SpaceX engineer, I'd be glad to answer any questions (on publicly available info) people have about the launch. Wish them luck!