There was a post on GAW yesterday that linked to a thread on tweeter claiming that a frame by frame analysis of the video shows conclusively that Kirk was not hit by a bullet of any kind, but that there was a small explosive charge in the wireless microphone attached to his collar. This charge supposedly turned the small magnet used to attach the unit to his collar into a projectile similar in size to some bullets. The thread also claims that Mossad assassinated someone earlier this year with this exact same method, basically a more sophisticated variation of what they did with the exploding pagers in the Middle East last year to assassinate terrorist leaders.

I have no idea whatsoever if this theory holds any water or not, but it was a fascinating read, and would answer some of the questions people have had.