Apple is expanding users ability to control how and when people talk to them on their iPhones in iOS 6. It has announced a new "Do No Disturb" feature that will continue to allow messages to come in, but your phone will not alert you to them until later. However, you can enable a setting where a second call from the same source will ring, so you're still reachable if it's an emergency. You can also set your Do Not Disturb to automatically turn on and off at scheduled times — say when you're going to bed — as well as allow calls from specific groups to bypass the DND setting and reach you anyway.
Apple is also adding a feature that has been bouncing around on various smartphones since the days of the Treo 700w, a "Reply with Message" option for incoming calls. Instead of simply answering or ignoring a call, the new feature will allow you to reply to the caller with a text message. You can choose from a few stock messages or enter a custom one.