Even though I wasn't that familiar with the whole Jim Jones/Jonestown story, I felt like they rushed through the early parts of the story...might have worked better at 2 hours than at 90 minutes. The ending is great, a well-paced mix of personal narrative, photography, audio, and video from the last fateful day of over 900 people. After the movie ended, I was trying to imagine what would happen if Jonestown (or to a lesser extent, the Branch Davidian thing or Heaven's Gate) occurred today. Religious cult leader brainwashes all these people and then kills 900 of them in the South American jungle, including a United States Congressman? CNN, et. al. would got nuts for a start...I don't know if 72 pt. type on their homepage would be enough. The blogosphere would probably go supernova as well.
The American Experience site has more information about Jones and the film. Check your local listings as well...you might be able to catch the film on PBS sometime in the next week or so.