How would I go about moving my iTunes library over to an external HD?

My iTunes library uses up about a half of my iMac’s hard drive, hence my desire to move it. I have a nice big external hard drive available… I’m just not quite sure how to move my library over. Not just my Music, but also my Movies and TV Shows. Anybody with any experience on this? (This question really makes feel quite noob-esq. :P)