Do Parallel Universes Really Exist?

A few years ago one of my friends mentioned the possibility of Parallel Universes.  At first I thought he was just some science geek, but later I became more open to this possibility.

go to this link:  http://www.pbs.org/wgbh/nova/elegant/program.html  and click on the program "Parallel Universes".

Imagine another universe where a double of yourself could be living simultaneouly.  In that universe things could be similar or could be drastically different.  Imagine another universe where the South won the Civil War.

Even the world we live in is full of frequencies upon frequencies many of which we cannot see or hear.

I have to admit the whole idea of Parallel Universes sounds crazy and how do you prove it?  It's something that will probably will never be proved.  Nevertheless, it's interesting and anything is possible in this strange universe of ours.