Your heading is Dock connector. Usually iPods come with a USB connector (?not firewire) which doubles up as a charger when plugged in to your computer. You can buy a mains plug adapter that takes the USB from the iPod or, if you buy a dock or speaker system they charge the iPod. I suggest a speaker dock with built in radio so you could replace old cassete of DVD / radio all - in ones.
Argos do cheaper iPod speakers / docks.