Wait... think about it! The Islamic courts do not condone this sort of thing. If he is tried in an Islamic court, he WILL be found guilty. Then, after the public beheading, there's a good chance that the rest of his network will say, "hey, maybe what we're doing really IS wrong!".
So, I think putting Bin Laden on trial before the US makes any attacks is a good idea. Hopefully the US/NATO can work it so a fair judge/tribunal/whatever handles the trial. Having a corrupt man presiding could be quite a problem.
Anyway, after the beheading... the organization will become weaker. Some people might drop out or attack other members of the group. This would be a good time for the US to step in and wipe the rest out.
But yeah, I think putting him on trial in an Islamic court is the best thing we could do to Bin Laden.