I have created a custom menu and put it in the footer http://seafordcinema.org/

How do I get the menu items to be in a horizontal line?

The WordPress custom widget menu is meant to be used in a sidebar which is why it shows the way it does. To get it to show horizontally, you will have to use CSS to style it.

I suggest using the firebug extension of Firefox to see what CSS is used in the header menu and adapt that to the footer widget area.