One thing I have always missed in OS X is the quick way to stop a print job. So this is my "Hello World" AppleScript to stop print jobs. It will delete all print jobs for all users on the local computer:
do shell script "cancel -a -"
Save it as an Apple Script application. I put it on the right edge of my dock. I also made it a login item. This is because my computer is portable and I don't want A's interrupted print job spitting out of B's computer. Works in Panther and Jaguar, untested in Tiger. Works with Appletalk and USB. IP printing often sends too fast to interrupt, but the application will kill a job if the printer is not on the network or turned off at the time you send the job.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20060210170203159