I was not there today but this photo at CERN says all:
CERN announced today the successful run of the first circulating beam in the 27 km ring of the LHC. You can find a communication here. There was a lot of excitement about this event but my view that this success is really tiny with respect to the findings will come out from CERN next years with this machine.
Blogosphere is rather active due to this. See the blog of Tommaso Dorigo that is there at CMS control room. Also Cosmic Variance has a real time report about this event. Tommaso’s blog has also some link to follow the event through video streaming (see here).
Update: A must read is the beatiful report given by Jester.