Check with your local Adult Education program or the language department of the nearest college. They can help steer you to classes for languages that may be a bit more exotic. Find someone who wants to learn English and exchange language lessons. A new immigrant from Guatemala may want to improve her English and be willing to teach you Spanish in exchange for conversations with you. Check out language tapes from your local library.
Tapes are a good way to get introduced to a new language.
Eventually you'll need to actually talk with someone, but tapes can help you get started with the basics. Watch television in another language. Many parts of the country now have whole networks devoted to television in Spanish, Japanese, or other languages. Develop your ear by watching soap operas or news in another language and try to figure out what is going on. Get a group of friends together and start a language club.