There's another way to do this... I bought a BenQ-Siemens EF-71 phone. It has an FM transmitter that allows you to not only play all of your music to your system but you can have your conversations transmitted to your head unit. Downsides - you need to search for an empty frequency and the transmitter isn't the most powerful I've seen. Upsides - it's a cheap way to accomplish this and it's a really damn cool phone.

I bought mine from Ebay from a guy in Taiwan. Try not to get ripped off - - - make sure it's unlocked (you can use any service as long as it has a sim card).
I paid $260 including shipping and got it in 7 days.