The new DJ Cable from Griffin works with the djay app by algoriddim to replicate the complete DJ experience, allowing you to mix any tracks from your iTunes library.
The DJ Cable's 'Split Output' function splits the signal and sends audio from your iOS device to a set of headphones and to your music system.
Algoriddim's djay app then gives you a virtual turntable and mixer setup on your portable, allowing you to queue one track in your headphones while your audience hears another.
The app also allows you to record your mixes or hit Automix to let the app sort out a playlist for you while you enjoy your party.
The Griffin DJ Cable is set to cost around £20, while the djay app, available from the iTunes Store, is currently £5.99 for iPad and £0.59 for iPhone and iPod Touch.