Spaceflight Now has posted an extremely detailed timeline of the Challenger disaster, including telemetry from the shuttle, transcripts of various verbal conversations, and some photos.
It's fascinating, but I couldn't deal with reading it in detail. Even skimming, it was still rough.
As Charles D. (who provided the pointer) noted, today is the 18th anniversary of the accident. He also noted that the Mission Control people seem to be remarkably calm throughout those transcripts; I imagine that's a combination of tone not being captured, emergency training giving them something to focus on, and the fact that they appear not to have been aware of just how bad it was for a while after the explosion.