ok. so you read the title. basically, it lets you listen to music in apps such as iParkIt, with headphones or the speaker. you're gonna need a device with iOS 4 or higher with multitasking abilities, and the apple headphones, or any other brand of headphones, but they must have the remote on them. 1. first, open the app. 2. plug in your headphones 3. open the multitasking bar up 4. the music play button should be greyed out. 5. press the play button for music on your headphones. 6. if you wanna listen through the headphones, you're done, just return to the app. 7. if you wanna listen through the speakers, don't close the multitasking bar, just press play on the headphones, unplug them, and you should be able to press play for your music. 8. return to app 9. enjoy the full awesomeness of multitasking.