From CBS NEWS:
"Republican Vice Presidential nominee Sarah Palin was prank called [...] by a comedy duo from Quebec, who convinced the Alaska governor that she was speaking to French President Nicolas Sarkozy."
She was prank-called= they played a prank on her on the phone.
They told her she was going to speak to N. S. and she believed it.
If you listen to the recording, you'll find the prankster told her many things that could have helped her understand this was a prank... but she just giggled each time the prankster said something ludicrous.
READ ALL ABOUT IT AND LISTEN TO IT!!