I haven't been able to gauge the interest in Harry Potter among folks here in St. Joe, but back in NY, every kid at church knew Harry Potter better than they knew the Bible. You'd discover this fact when teaching them Bible stories and they would naturally draw comparisons to events that happened in the book series--which sort of speaks to the Christian influences that Rowling naturally seems to stick into her narrative. I had no choice but to engage Harry Potter in order to communicate with kids, just as I engaged rap and hip-hop with the youth group in order to speak to them. I know a lot more about Harry Potter than I do about rap--as the kids in the youth group would constantly point out to me.
Apparently, the Church of England has a study guide and resources for using Harry Potter at church. That works for me, since I'm a big fan of the book series, and just as I enjoy book clubs, movie watching, etc. with church folks, I'd also enjoy discussing Harry Potter.
Terry Mattingly has another column on Harry Potter and its reception among church folks. I found interesting the comparisons between Rowling and C. S. Lewis' Narnia series. Although I loved Narnia, I have to say that the Potter books are a lot more fun--Lewis' allegory grew a bit weighty for me even as a kid.
Grace and Peace,
P.S. If your up for an irreverent pardy of the Religious Right's reaction to Harry Potter, check out the fzux Potter protests at the make believe Landover Baptist Church web site.