A quick search of freshmeat brought some possibilities:

http://freshmeat.net/search/?site=Freshmeat&q=call+tracking&section=projects

meg@leary.csoft.net wrote:
> 
> I am looking for a web based call tracking/techsupport
> system. I half created one from perl/mysql a while back ago,
> but I fear I will not have time/funds enough to finish.
> 
> Does anyone hapen to know of a descent system already
> out in the wild?
> 
> Perl/MySql/Apache is preffered, but I certainly
> wouldn't mind going the PHP route instead.
> 
> I did a couple google searches, but I ran into sooo many hits
> I was kind of hoping someone here might save me a bit
> of experimenting time.
> 
> v/r
> Mike
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