VoIP Latency & Jitter

I’m trying to find a source of information about maximum latency and jitterallowable on PC networks running Windows TCP stacks. I’ve been given some anecdotal figures of 10ms latency and 2ms jitter. Do these sound reasonable to anyone? Or can someone point me to a source of information that is reliable? Or more substantial?
Would you be so kind as to drop me an email if you have any info which might help me to obtain this info?

Thanks

peter.strong@nsine.com