First, it was a few people who wanted to get work email on their personal iPhones so they could keep up with the office even if they weren't there. Then it was a couple of high level people who decided they'd get iPhones as their official company phone. Now you have stacks of them all over the place and people are starting to ask questions about managing this many devices and security policies andurgh! What ARE you going to do about all of that?
Instead of the heart attack you're likely considering at the moment, let me make a different suggestion: Check out the new Mobile Device Management Primer from MacTech! First and foremost, this is a FREE resource. Really. Go get it. It's THAT simp