I disagree that you can learn a foreign language easily by hanging around people that speak that language, particularly if they are bilingual. It is a big effort to speak to someone who is not fluent, and people generally don't want to. Whether in the U.S. or abroad, you need to study enough to hold a simple conversation before you can effectively interact with people who you are not paying for lessons.

Most people go abroad for a limited amount of time. You should study tapes before you go, to use your practice time there effectively.

I think the Michel Thomas tapes/CDs are the best to start with, for the languages they are available in (mostly Romance languages). After you are done with these you can switch to Pimsleur for more study.

I found that the Michel Thomas tapes are enough background that you can have simple conversations, which of course is only the start of learning a language.