I'd recommend watching Nightblue3 http://www.twitch.tv/nightblue3
He's a high elo jungler (challenger the past two seasons, working his way up to challenger again now), and he does a good job of teaching the game, especially the basics of jungle. He usually plays carry-style junglers, but if you're just starting out I'd recommend you stick to junglers with better sustain; I learned how to jungle with Phoenix Udyr, so that's my personal recommendation, but Warwick is also a good choice. Once you start to get the basics of farming efficiently, when and where to gank, maintaining vision control, tracking the other jungler, etc. you can start to branch out to other champions you feel comfortable with.