What is the minimum validity required on my NZ pport to enter the US?

I am flying from Auckland, New Zealand to Los Angeles, USA on 13 August 2010 for 4 days (Pleasure) and returning to Auckland, New Zealand. I have not been successful in finding any information on pport validity. My pport will expire on the 10 October 2010 and I have been granted ESTA under the waiver programme.