My wife and I are cruising the Eastern Med on NCL on Oct. 15. I've arranged private tours in both Istanbul (pre) and Athens (post) and am contemplating a couple of private tours in lieu of ship tours during the cruise. I found the tour guides by doing extensive research on the internet and corresponding with others who have used private guides. My one piece of advice (which I decided early on to adhere to) would be to ensure that any private tours you book do NOT require any advance payments or deposits whatsoever. The tours I've arranged for will be paid for at the end of the tour. By doing this you should have litttle or no concern with getting "taken".