The iPhone has included a Clock app with an alarm feature since it first debuted in 2007, however until recently the ability to wake up to a song from your music library has been conspicuously missing—a particularly odd omission considering that the older, traditional iPod models have supported this capability for close to a decade. The good news is that iOS 6 finally delivers this capability, if only partially; in the iOS 6 Clock app, you can now choose a specific song from your music library to play when a given alarm sounds, however support for starting an actual playlist remains absent.
To set this up, simply go into the Clock app and create a new alarm or edit an existing one and choose the “Pick a song” option for your alarm sound. This will open the music browser where you can either search for a specific song or browse through your library by artist, album, genre, or playlist. As an added bonus, the Clock app will display a list of the most recent five songs that you have selected, allowing you to easily re-use them for additional alarms in the future.