AUX/iPod sound input via CD Changer port

Hey folks, I'm looking for the simplest solution to hook up either an auxiliary sound source or an iPod. USA Spec makes two adapters, one that is simply a line in. Right now this is the direction I'm leaning in.

I've got the 2002 GT Premium with six CD changer. Are there other makes/models for AUX inputs that anyone here has experience installing or using?