Master page layout question

I have the a simple master page.  I now want to add a menu that will display vertically down the left side of each web page.  But I can't seem to figure out how to get the content to display to the right of the menu instead of underneath the menu.  Here is what I have so far in my master page:
<%@ Master Language="C#" AutoEventWireup="true" CodeFile="CustService.master.cs" Inherits="SiteMaster" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head runat="server">
</head>
<body>   
  <form runat="server">
   <div align="center">
    <asp:Menu ID="Menu1" runat="server" BackColor="#B5C7DE" Dy ...