Seth Godin has a post up called Marketing Morality that deals very well with the ethical questions surrounding marketing.
It hits the nail on the head in terms of what marketing is, why it isn’t inherently evil, as some assume (especially when it comes to "church marketing"), and when marketing actually does become morally ambiguous. It’s a killer article, and one that church leaders should read.
Bonus link: Church Marketing Sucks. Here’s another guy who’s extremely thoughtful about "church marketing" and how it can be done in an un-evil way. Hint: it’s not marketing that’s bad, it’s bad marketing that’s bad.