When my iPhone 3GS screen locks, the signal to my Bluetooth headphones fades out. My iPod Touch works with the same headphones perfectly fine locked.
I cant find a setting for "Keep Bluetooth Working After Lock"
My fix was to set the phone to never lock. But then the battery dies after only a few hours. So then I started turning the brightness down to nil to save battery. But then when I get a phone call, no screen

Anyone have any idea how to fix this?