This is probably the best quick-start guide:
http://www.youtube.com/watch?v=tiCiehJAFSg
My best advice is to watch a game, on televison or DVD, with someone who knows rugby. That way you can pause and rewind the action, and ask all the questions you want. I think it is difficult to learn rugby standing on the sidelines of a college/high school game, because your point-of-view is not optimal. Like hockey, you want to watch it from more of a bird's-eye angle unti you get familiar with it. Othewise it turns out looking like pure chaos.
Learning rugby is not super easy, but once you've got it down, it's a blast.