If you went to an interview and they said the would call you by a certain date but they haven't called should you call the next day or wait a few days?

I would call because it's within the bounds they gave you - plus, it shows interest.

It is appropriate to call after one or two days. I agree with the above post that it shows that you are interested and that you are willing to put in extra effort to get the job.

The last job I got, I waited two days after a great interview and then called the employer... to my surprise, he said that he had been waiting for me to take the initiative to call.

Bottom line, employers want to hire someone who wants the job. You don't have to call every day and harrass the person, but it can't hurt to let them know that you are serious about the position.