iLounge

It's a pretty inelegant solution, but with Apple's restrictions on Lightning-compatibile accessories, CableJive's dockBoss+ iPhone 5 Kit ($30) is one of the few options on the market right now for using older Dock Connector-equipped accessories with the new iPhone and upcoming iPods. At one end of the cable is a female Dock Connector port, and the other has female USB and audio-in ports. CableJive includes a 3.5mm audio cable, but you must provide your own Lightning cable, which gets plugged into the female USB connector. You then attach the Dock Connector to whichever older accessory you want to use. This will allow you to play audio through devices that have a built-in digital converter; pure analog systems will instead need the audio line to be plugged in.