On the EVO. This is how I did it. Settings > Wireless and Networks > Bluetooth Settings
You should see "Bluetooth Devices" and under that it should say "PIONEER NAVI" or something of that nature assuming your devices are already paired.
Long hold "PIONEER NAVI" and another menu comes up.
There should be an "OPTIONS" button.
Both "PHONE" and "MEDIA" should be checked.
If they aren't both checked. Check "MEDIA" first. Try to see if it will play via bluetooth using the stock Music Player app, Pandora or Double Twist. The stock music app, Pandora or Double Twist will