I hunted my first cape buffalo with Martin Pieters last June and recommend him highly. His Omay concessions are crawling with buffalo, I saw over 300 the first two days of my hunt.
This is a list of Zimbabwe PHs. There are some discrepancies. If you do not see your PH on this list contact SOAZ or ZPHGA. Also it is not updated for 2011.
Douglas Duckworth and Dalton Tink both passed the exam in 2011 and are now licensed PHs as are several others I do not know.
Dalton Tink is Martin's nephew and he was an apprentice in camp while I was there.