Automatic filling the whole browser window

Hello

I want to do something like on: puma.com.

My first problem:
So one image (a .jpg) is the background that auto-scales to fill the whole browser window. But what is the best way to do this?

My second problem:
I have content that I want to have at a certain position (on every browser window the contant must stand absolutely left for example), but how can I place it there when everything scales automaticlly?

Thanks in advance
Niels T.