Any major library has language acquisition books, and among these are Italian language books. If you do not have a library card, you may obtain one for free. Start by consulting books at your level (Beginner, Intermediate or Advanced) and regularly follow the lessons closely. Most language acquisition books come with CDs for listening exercises and some even contain additional CDs that you can put in your computer to access grammar exercises.
On the Internet you can find many websites offering free language courses. These are self-paced, and sometimes offer information that is delivered regularly to your email address. The best websites are those that work on an exchange basis, meaning that native speakers of one language correct language exercises from native speakers of another language. Additionally, you can access lessons as a podcast and download them to your MP3 device to take with you wherever you go.
A free and efficient way to learn a foreign language is to set up a "language exchange" with a native Italian speaker who wants to learn your language. In these situations, both individuals meet regularly at a public place and give each other lessons in their native language. You can find a native Italian speaker interested in these types of language exchanges by posting ads on Internet forums, through local universities or even the local Italian consulate or embassy, if possible.