Port Security with Voice over IP

Greetings;

Our company will be implementing Voice over IP in the not too distant future. I was wondering if anyone has implemented Port Security with VOIP and how they achieved it. We are looking at VMPS, 802.1X or even something called NAC.

I’ve read up on the subject and understand that in restricting MAC Addresses you will need to secure three (Phone, Computer and ASIC in the VOIP).

Thanks to any and all who could help.