How does your body respond to nerves?

I'm about to do a phone interview with someone whose quite a big deal (well, in an incredibly niche area), and have the jitters. Foot tapping, hands skittering, worried about controlling my voice. I haven't had enough of a run up for my digestive system to come into play, but I'm sure it would if it could.

Do you ever get nervous, or are you THE FONZ?