Sure, it’s great that all you have to do to silent your iPhone is flip the switch on the side, but then you’re at a loss for telling the difference between an important business call and your neighbor who’s looking for someone to watch his dog. Fortunately, iOS 5 offers a relatively simple way to set up custom vibration patterns for different contacts, so you’ll know when you really need to pick up.
First, open up Settings, tap General, tap on Accessibility, and turn Custom Vibrations on. Next, open Contacts, choose the contact you’d like to have a special vibration, and tap Edit.
You’ll see a new field next to ringtone called vibration. Tap it, and you’ll be on a page where you can select from a handful of preset vibration patterns, with an option for creating a custom vibration at the bottom.