Car stereo place to install line-in in my Jeep (5 replies)

My 2002 Jeep Grand Cherokee doesn't have any way for me to plug my Ipod in. Does anyone know a place that can install a line-in? Now that I think about it, do you think the speakers would sound any better if I had them replaced or anything? I listen to a lot of music and also audio books, do a lot of driving.

Thanks