Decide if you want to study Brazilian Portuguese or Continental Portuguese. Though they are fundamentally the same, there are dialectal differences, much like American and British English.
Go to your local library. Search for Portuguese language lessons. You will find cassette tapes, compact discs, books, grammatical exercises, and cultural materials. If your local branch has none, chances are good that one of the other branches will have copies. You can get a variety of resources and practice in many different ways. You can also check them out as often as you like. This is also a good way to decide if you want to actually purchase any of the programs.
Look at your local universities and community colleges. See if any Portuguese classes are being offered. Sometimes, colleges will allow a current student to audit a class. You will be required to attend and do all of the homework. You'll also be given the opportunity to take all of the tests, but you will not receive an official grade in the class.
Check local community boards at your local library, bookstores, coffee shops, or grocery stores for any groups that may be meeting to speak Portuguese. Sometimes there are others like you who wish to practice what they have learned. Sometimes native speakers wish to reach out to other native speakers to feel at ease. Many times people are honored that you wish to learn their language, and they will be willing to help you.
Create your own group. Post notices at your local library, bookstores, coffee shops, or grocery stores. Seek others who would also like to practice Portuguese. You may also be able to trade materials with people.
Read the back of your favorite DVD. Some movies have language tracks that are in Portuguese. You may pick up some new vocabulary. More importantly, your ear will become used to the sound and flow of the language.
As you learn new vocabulary words, write them down on flashcards. Review your flashcards daily. Practice Portuguese for at least fifteen minutes a day, and you will find yourself becoming more proficient very quickly. Boa sorte!