After purchasing a new device or upgrading your device to iOS 7, you may notice that the AirPlay menu is no longer accessible.
iOS 7 moves the AirPlay menu to Control Center. Control Center can be accessed by swiping up from the bottom of your device's home screen. This menu can also be accessed from the lock screen without unlocking the device.
More information can be found in this blog post.
Additionally, Apple has provided instructions for connecting devices on their support page.