you're looking for is audio streaming via A2DP bluetooth profile. this needs to be supported by the headset/headphone (ie. stereo bluetooth) and the device itself. AFAIK, the iphone does not support A2DP. my belief is that Apple would much rather you buy/invest in their proprietary accessories, docks, and cables than use an open standard. however, i think there are some third party dongles that attach to the iphone that may allow this stereo audio streaming functionality.