It depends on which company you applied to and how busy they are at this moment with job applications and such.
The earliest I've heard back was two days and the latest I've heard back is that they didn't get back to me at all. I think you should wait for three months at the very most.
When they haven't gotten back to you then, it's most likely because they aren't interested in hiring you anymore. Most companies actually say this on their application I believe (or at least the places I've applied to said that).