I have a cell phone model and I want to have a little charm or key chain like item hang from it.

So this is what I have:

1) Cell phone model
2) A little "plastic" charm
3) A string attatched to both

What I'd like it to do is when I move the cell phone the string swings around moving the attatched charm on the end of the string.

In my animation I'll need to do things like have the phone on a table or in a pocket, have a character pick it up and put it down. SO somehow that string and charm can't go through itself or said character.

I know this is really complex. I looked around at all sorts of tutorials and played around with my own ideas, but I'm just not knowledged enough in Maya Dynamics etc. I'm modeler mostly trying to learn animation.

Any help or advice would be great.

Thanks a lot.
-George