Depending on what company you interviewed with, it could be MONTHS before you hear anything. Our son interviewed with a major medical center at a university. They sounded very interested in him, but then he didn't hear anything. He took another job. Two months later they made him an offer, but didn't say when they wanted him to start. He accepted their offer, but kept working the other job. Several weeks later, they asked him to start in about a month. It's a darn good thing he didn't just wait for them to get around to hiring him. He works there now, and is learning a lot on the job...but it was a loooooong process.
Not all places are like that, but some are. It's worth a phone call, to politely let them know that you are still interested in the job, and to ask if there is any other information you could provide them with.