How do you access the auxillary input to use an mp3 player on a Ford Focus?

I recently purchased a 2005 Ford Focus SE Wagon and was trying to figure out how to hook up my mp3 player (Zune) via the aux input; however, I cannot figure it out. From the research that I have done, it appears to be located on the back of the head unit. Is this true and if so, how would I go about accessing it. Would it require the purchase of an installation kit, etc.....?How do you access the auxillary input to use an mp3 player on a Ford Focus?I could be wrong but I don't think there is a aux port on the radio. There is a special plug that you need for your mp3 player to work. You need to get a wired mod. Go to Circuit City back to roadshop and get it. it is 50 bucks and they will install it for another 50. You will also need a Y cable that the install guys will need to install everything. I know this b/c My Ford 500 uses this same wire. Also if you need anything else feel free to email me. Hope I helped DUECES!!!