On September 8, 2009 (20 Elul, 5769), the Baltimore community had a Kinus Hisorarus (communal gathering) for men on the topic of Tznius. The Rosh Yeshiva, Rav Aharon Feldman, Shlita, was the first speaker, and set the tone for the entire evening. Although the Rosh Yeshiva did not directly address pornography or the Internet, it's not difficult to apply much of what he said to the challenges we face.
Especially on point is what the Rosh Yeshiva says near the end, about how breaches in Tznius (men being attracted to other women, and women trying to attract other men) have a profound effect on our Shalom Bayis.
The Rosh Yeshiva's speech is just under 20 minutes, and can be downloaded here.
Rav Dovid Heber was the final speaker at the Kinus Hisorarus. His topic was the challenges of technology and immodesty, both in and out of the workplace.
Rav Heber's 35-minute speech includes sharply criticizing Facebook (and other social networking services) early on (3:00-4:50), as well as mentioning both GYE (10:05-10:11) and Internet pornography addiction (20:50-20:59). Rav Heber has strong words about how many of us live double lives, and how contradictions in how we live and what we expect from our children can, c"v, have very negative effects on how they turn out (20:17-29:41).
Rav Heber's speech is around 35 minutes, and can be downloaded here.