Not a great stream, but it appears to be live:
http://www.dailymotion.com/video/kvJk3BlksPLQKgK3I3
[NBC is on delay, will show later tonight.]
The actual ceremonies were this morning. When I was looking for last minute pictures, they were posting ones of the closing ceremonies.
NBC claims their coverage will start at in about 5 minutes, but I bet we have to sit through 30-60 minutes of fluff first.