It is not possible via bluetooth on Android, only from phone to PC, not from PC to phone... But here are some solutions you may be able to use:
The easiest way to do it is using this app: https://market.android.com/details?id=com.georgie.SoundWireFree&rdid=com.georgie.SoundWireFree&rdot=1&pli=1
Another way to do it is to use splashtop remote, which uses your wifi or 3g to remote control your pc, and sends hi quality audio and video to your phone, but if you are on 3g it can use a lot of data, so it can get expensive...
The next thing is to use AirBubble app and Airfoil to stream audio from pc to Android device
http://forum.xda-developers.com/showthread.php?t=1051623
http://www.rogueamoeba.com/airfoil/windows/
I hope you found this useful...