don't spend the extra money on the Mp3-ready stereo. the standard ones all come with the AUX input. just get an ipod, put your cds into it (through itunes), and you're set.
the 1/8" AUX cable is like 2 bucks at radio shack, and it works great. you just have to have your ipod at like 70-75% volume to it doesn't distort (like the transmitter). only problem (small one) is that when you switch to normal FM/AM or CD, it will be a lot louder, since you have to compensate for the lower output on the ipod.
still better than CD though, by far, heck, for the price you would pay for a six-disc/mP3-ready sterero, you can get an ipod. trust me, you won't regret it
*this is a paid advertisement from Apple, all hail Steve Jobs