The Apple Store has "content boxes" around logical groupings of things, seen here.

Some related questions...

1.) How are those created?

Are they just DIVs?

2.) How can you create the rounded corners without using CSS3?

3.) How do you create the subtle shadow ate the bottom of each box?

4.) If those are DIVs, then how flexible are they if I use a "Fluid" layout or at least an "Elastic" layout?