http://neo.jpl.nasa.gov/news/news160.html

Infrasound detection of the fireball:

Impact of Asteroid 2008 TC3 Confirmed
Don Yeomans
NASA/JPL Near-Earth Object Program Office
October 7, 2008

Confirmation has been received that the asteroid impact fireball
occurred at the predicted time and place. The energy recorded was
estimated to be 0.9 to 1.0 kT of TNT and the time of detection was
02:45:45 on October 7 (Greenwich Standard Time). More details on this
detection will be forthcoming. An addition confirmation was apparently
reported by a KLM airliner (see: http://www.spaceweather.com/). As
reported by Peter Brown (University of Western Ontario, Canada), a
preliminary examination of infrasound stations nearest to the predicted
impact point shows that at least one station recorded the event. These
measurements are consistent with the predicted time and place of the
atmospheric impact and indicate an estimated energy of 1.1 - 2.1 kT of
TNT.