Using a iPhone 5 as a bluetooth receiver/audio sink
I have the same question (but PC -> iPhone)

Here is a bit more information to help, connecting iPhone -> PC you are able to have an audio sink service on the PC where all sounds from the phone will play through the computer speakers but not where the phone is the sink (receiver)

If you connect a laptop to a PC you are able to have either as the sink (receiver).


Answer: 

As far as I am aware Apple has blocked the Bluetooth Audio Sink Service on (at min) the iPhone (4S IOS7)