How to block a number on my iPhone? - 1

This number keeps on calling me, and I picked up and didn't say anything. Silence was all I got, and some sounds from the TV. Then he said something, but I'm not sure what and hung up. So I need to know how to block a number from my phone, or at least find out who called me, preferably for free.

I know where you're coming from. I've had calls like that and the first thing I do is call my telephone company and have them block the caller's number in their database. That filters all the caller's future calls from coming through.

And after I block them, I report the phone number to http://www.callercenter.com to raise a warning about the prankster. With about 40 000 visitors daily on the website, I'm hoping that a portion of those 40 000 will prank call the prankster, too.