We're now 45 years away from the assassination of John F. Kennedy, and we don't particularly seem to have any more answers than we did shortly following the event itself. The National Archives has some of the documentation, so of you're interested in pursuing your own theories, go right ahead. This being 2008, various permutations of the Zapruder film are available on YouTube. Here's one that seems like it's been stretched a bit but appears to be relatively complete.
As we get further and further away from the event itself, the details become hazier and hazier and it becomes more and more difficult to work out whatever actually happened. But theories and research will continue to go forward, and who knows--maybe one of them will point us in the right direction.