So you want to turn off Apple's annoying crash reporting. I did, because PythonOgre application crashed for several minutes; since the python process could not be 'kill -KILL'ed, which is very odd on a UNIX, I concluded the problem must be with Apple automatically collecting post mortem debugging crash information.
So in order to disable the crash reporter do this:
sudo launchctl unload -w /System/Library/LaunchAgents/com.apple.ReportCrash.plist
This works on Leopard 10.5.8. Also it's somewhat at odds with Apple's manpage for ReportCrash.