Two excellent articles on the impact of pornography on the ministry (and, by extension, on Christian lives in general):

William Shishko, `The Perils of Pornography on the Internet' in Ordained Servant 15 (2006); the journal is available via www.opc.org.  Like the last chapter of John Armstrong's excellent The Stain that Stays (CFP), this article contains good theological analysis and sound practical advice from someone with years of pastoral experience.

Eric Reed, `Hooked' in Leadership Journal (Winter, 2001).  This article is, quite simply, terrifying. I cannot recommend it highly enough.  It reminded me of the old sex education videos on STDs that they showed at my school which achieved the almost impossible feat of persuading classloads of 15 year old boys that a life of total celibacy really was the best option.   I would say that this article is essential reading for anyone thinking of pastoral ministry; and the head of PT at WTS, my good friend Tim Witmer, is aiming to make it so for all MDiv pastoral students.