Forum Background image (forum,cms,blog the whole lot)
 

My site - http://www.eteknix.com
My inspiration - http://www.hardwareheaven.com/

As you can see they have the gaming theme background. I'm trying to do something similar with my site to offer to potential sponsors for advertising to skin the site.

So i have a couple of questions:

1. What size will the image need to be to fill the space like the one in my link?
2. How do i get it to NOT scroll when you scroll down the page so the background doesn't move?
3. How do i make the background image linkable so that it links to another site?

Many thanks,

Andy