clipped from: www.attackr.com   
It’s simple to turn a regular image into a clickable link, but in some situations, it’s just not possible to use a regular image - so how do you turn a background image into a clickable link?

So, how can we make our background image a clickable link? It turns out it can be done with a clever CSS trick. All we have to do is add the link markup between our header div tags, and apply the above markup to the link instead. All we have to add to the CSS is display: block to force the link to fill the entire space.