Adding an aux cable to a car stereo?

So, in the picture you can see the back of my car stereo.
image

The thing is - it does not playback mp3 cds, so I want to add a cable, so I could plug in my iphone.
I have read that one can add a aux cable or smth so that it is possible to connect mp3 players (with a 3.5mm jack). How should I do it?

P.S. The stereo is from a Chrysler Sebring 2006.

And please don't suggest Fm transmitters.

O.K. I won't suggest an FM transmitter. Get a new radio if you want an aux connection. Getting your current radio converted/upgraded will cost more money than a new radio.

There's NO POSSIBLE Way to connect your new technology to old technology. Toss that stereo into the garbage and buy an aftermarket unit that has the aux connectors.

Stay away from FM modulator they don't work, on the back side of your radio there's a free plug, that is for the external Chrysler cd changer or auxiliary input
installtion is simple and will work with the Mode button from your Chrysler stereo this is what you need
http://www.oemautosound.com/pc-188-84-chry02-aux-chrysler-auxiliary-audio-input-adapter-2002-2007.aspx

and this is a video instruction with the same radio

this is the iPod Chrysler adapter