Thanks for sharing your Fogbugz trigger. I've been pondering playing with Fogbugz, now I have a good excuse!

Actually, one good thing to add would be a license of some sort, just so folks know how they are allowed to use and extend your tool. Here at Perforce we tend to use a 2-clause BSD license, but there are a variety of options. http://opensource.org/licenses

the original script didn't come with any sort of license, so I'm hesitant to do anything official:
http://help.fogcreek.com/7868/integration-with-perforce?se_found=1

That said my rewrite and modifications are posted here so that anyone can use them as they see fit.

A typical fogbugz update is shown in the attached screenshot. We use "[case: xxx]" fogbugz case notations in our p4 checkin descriptions.

I followed up with Fogbugz and they've given you clearance to open source your script and license it as you wish. All they ask is that you add a bit of verbiage to it somewhere saying they aren't responsible for any bugs. =)