When we were in Rome, I bought a very useful little book called Supplemento al dizionario italiano by Bruno Munari. It's a dictionary all about hand signals, and what they mean in Italian. There's a picture of a hand making the symbol, and then translations in Italian, Englis, French and German.
For example, they do OK just like we do - by making a circle with their thumb and forefinger tips together. Then there's a short description and info. Like, "This gesture is a recent import from America, and is not yet very widely used in Italy. The forward movement is sharp and short, then the hand is held motionless."
We went through the entire book with our Italian friends, who taught us some of the finer points of some of the signals. It was fun, because we were able to communicate with each other on this whole different level! Sometimes I would challenge M with a long sentence and ask him to say the whole thing in hand signals. He was really good at it.
Here are some of my favorites... This one means "Rage" you pretend like you're biting your finger.
and this one is like, "Who's with me?" You put your hand out, and everyone who's "In" puts their finger in your palm. Cute, right?