Job Monitoring...

Hi,

I would like to launch an application whenever a job is created, the 
application launched will monitor the job progress and report any errors to the 
user. How should one do this on MAC OS X ?

1.Should I write CUPS filters to launch my Job Monitoring application ?

2.Should I write a  Printer Module(PM) to launch my Job Monitoring application 
? if yes how do I register a PM for a particular queue during the driver 
installation ? Can I just hook on to the "BeginJob()" and then call the PSPM 
for the remaining functions ?