While you could probably get by without speaking any Italian, the better you speak the language, the more fun you'll have: you'll make better connections with locals and the language itself is fun. Also, learning Italian makes it easier to learn other Romance languages like French or Spanish. Here is some stuff to get you started:
Here are a few survival phrases that every person visiting or living in Italy should know.
The basic italian page will teach you a bunch of useful words and phrases, that will get you well on your way to understanding and being understood.
See the pronunciation page for details on how to pronounce Italian words.
Methods for learning and improving in Italian.
Useful books, tapes, software, and websites for learning Italian.
It might be said that Italian is really a sign language with a few words thrown in for color. The gestures page summarizes some of the major Italian gestures.
A fun, effective way to learn Italian is to learn Italian songs. It's also a great intro to Italian culture.
Try your hand at learning the native "dialect" of Naples—also the language of many popular "Italian" songs
Italian is similar to French is a lot of ways; learn how to parlay your ability to "parler" French into Italian.
Italian is so similar to Spanish, sometimes you can get away with speaking it and Italians will understand you. This page will help you learn the key differences between Spanish and Italian so you can be truly understood.