Sharepoin Layout and hide ribbon

1)      Open your SharePoint master page

2)      Locate this line: <div id=”s4-ribbonrow”>

3)      Change it to: <div id=”s4-ribbonrow” style=”display:none”>

4)      Now find the end of the “s4-ribbonrow” tag and add following block right after it: <Sharepoint:SPSecurityTrimmedControl ID=”SPSecurityTrimmedControl2″ runat=”server” PermissionsString=”AddAndCustomizePages”>     <script type=”text/javascript”>         document.getElementById(“s4-ribbonrow”).style.display = “block”;     </script> </Sharepoint:SPSecurityTrimmedControl>

5)      Save the new master page and publish it.

Reference:http://blogs.msdn.com/b/zwsong/archive/2010/04/29/how-to-hide-ribbon-from-users-without-edit-page-privilege.aspx