Hey there, SLKMan, I've read before that attempting to use the oem microphone with anything other than oem phone will result in less-than-desirable performance. You could probably get it wired up and used with an aftermarket bluetooth setup, but I'd hate to spend the money just to find out it has poor performance.
I don't know what kind of stereo setup you currently have, but my solution was to install an aftermarket stereo (
Blaupunkt Hamburg MP57) with bluetooth capability. It's perfect for me...I've used it for a couple of months now and can't complain about it's performance in any way. When I turn on my vehicle, the stereo automatically links up with my phone and it uses the stereo speakers like you mentioned. I got it at Crutchfield for $200. Let me know if you want to see a pic of my setup.
Mike