Brian Bernius teaches Old Testament in the undergraduate School of Theology and Ministry here at IWU. He's about to defend his dissertation at Hebrew Union. He gave a great presentation on the Philistines in the Latter Prophets at the Theological Research Seminar we have on campus at 4pm on Mondays.
Great stuff! His work will undoubtedly become the standard "go to" resource on the Philistines. His main thesis on the Philistines in the Prophets is that references to the Philistines are mostly geographical-political in nature rather than ethnic. They are the people to the west, the people who live in the five cities. It is an external rather than internal term. It refers to the people in a place rather than making a statement about culture or ethnicity, other than the obvious fact that they are non-Israelite.