When this app (douban.fm) is running, the default volume bar could control it playing/next instead of the iPod app. and there's a play icon in the status bar. and I believe the headset control could control the app as well.
I'm developing a similar music app and wondering how to accomplish this functionality that when my app is running, users could use the control bar or headset control to play/next?
the play icon in status bar (near the battery icon)
https://picasaweb.google.com/nicoster/201134?feat=directlink#5580079059148648786
system music control now controls douban.fm https://picasaweb.google.com/nicoster/201134?feat=directlink#5580079159380140162
see this question. I think it'll help :)
How to enable iPod controls in the background to control non-iPod music in iOS 4?