Crank Pulley?

Please forgive me if this is already posted somewhere on your site. I did a search and did not see anything.

My sister called me yesterday to tell me that on her way home from work she heard a screeching noise on her 2000 Nissan Frontier. Further inspection revealed it was the pulley attached to the crank. Now from her observation it appears to be three different pulleys, A/C, PS, and alternator. The last pulley (one closer the block) was wobbling like crazy, that was the culprit of the sound.

I have tried to do research on this, thought it was called a crank pulley, but those look like they only have 2 pulleys. I have not seen the truck because she is an hour and a half away. I am trying to get an idea of what is going on before I head that way.

So....

Has anyone seen this before?
What is the name of this pulley? How much is it?

Thanks David

Here is a picture of what my sister sent. The top of the pic is the one that seems to be broken. The other picture is what I found on the Internet. Is this what I need?