Decide on the best method for you to learn Italian: an audio tape or CD or a book, or a combination of both. For conversational Italian, a CD should suffice. If you learn best with visual aids and think seeing the text will help you, consider an accompanying workbook.
Review the different language packages out there, taking into consideration any time constraints you have. Rosetta Stone is highly rated, but also very expensive. Basic books from large, trusted companies can be effective, such as "The Complete Idiot's Guide" and "For Dummies" series, and many of these are available to download on iTunes. Bookstores and public libraries also have "Italian for travelers" types of books. Read reviews on sites like amazon.com before making your purchase.
If you choose to learn by CD, follow the recommended listening guidelines. The people who have designed these programs know best how they work. Trying to learn too much too fast will not be effective, nor will simply popping in the CD during your flight to Italy.
Expose yourself to the language. Rent some Italian films and watch them a few times with and without captioning. If you are a visual learner, it will be helpful to watch the film with Italian subtitles to catch the words you might miss when they're spoken. You can also listen to children's Italian music CDs, which often have simple, repetitive language.
Practice! If you know an Italian speaker or someone else who is trying to learn the language, talk with them in Italian. Seek out an Italian language institute near where you live, or use Craigslist to find tutors or native speakers who might like to help you practice.