* {margin:0;padding:0}

Just wondering why is the * needed for this to work?

It isn't needed at all. The * just means 'apply to ALL elements'. You could just as easily do this:

body, ul, h1, h2, h3, h4, h5, p, li, ol, #content, #nav, #container{ margin: 0; padding: 0;}

Soooo.. which would you rather type ?? Zeroing out the margin and padding on all elements levels the playing field so you can style all elements as YOU choose.

Shortcuts like that can make your code much cleaner and easier to read!

The name of the css object