You can either specifiy a width for the entire menu, with padding or alternatively you could use position:relative;left:… px to move each menu item.
eg: The following would give an 840px wide menu with 20px of padding between the edges and the menu items:
[code:lbhdsd7n]#suckerfishnav {width:800px;padding:0 20px;}[/code:lbhdsd7n]
And the following would move the menu items 20px to the right:
[code:lbhdsd7n]#suckerfishnav li {position:relative;left:20px;}[/code:lbhdsd7n]