PowerShell: SharePoint 2010 Add top/Global navigation links and sublinks

This works for SharePoint 2010 sites with the Publishing feature enabled.
Before getting started, populate the header, title and URLs in an XML file (I am saving this in a file called topNav.xml).

Sample format:

 <Navigation>  
      <Group Title="Sites">  
           <Link>  
                <Name>Asia Pacific</Name>  
                <Url>http://asiapac</Url>  
                <Target />  
           </Link>  
           <Link>  
                <Name>Canada</Name>  
                <Url>http://canada</Url>  
                <Target />  
           </Link>  
           <Link>  
                <Name>Europe</Name>  
                <Url>http://eu</Url>  
                <Target />  
           </Link>  
           <Link>  
                <Name>Japan</Name>  
                <Url>http://japan</Url>  
                <Target />  
           </Link>  
           <Link>  
                <Name>Penang</Name>  
                <Url>http://penang</Url>  
                <Target />  
           </Link>  
           <Link>  
                <Name>United States</Name>  
                <Url>http://states</Url>  
                <Target />  
           </Link>  
      </Group>  
 </Navigation>  

And here is the powerShell script to grab the values and populate the Global Navigation section.

PowerShell: Update target Audience of a SharePoint 2010 Web Part

 # Get reference to the SPSite object  
 $SPWeb = Get-SPWeb "http://sharepoint"  
 # Get reference to the landing page. Since it is a publishing site so default.aspx is the landing page   
 $page = $SPWeb.GetFile("Pages/index.aspx")   
 ### Uncomment the lines below to perform the update  
 #$page.CheckOut()   
 # //Get reference to the webpartmanager class   
 $webpartmanager = $SPWeb.GetLimitedWebPartManager("Pages/index.aspx", [System.Web.UI.WebControls.WebParts.PersonalizationScope]::Shared)    
 # Double check the web part that you wish to update. Iterate through webparts in webpartmanager class   
 for ($i=0;$i -lt $webpartmanager.WebParts.Count;$i++)   
 {    
      #write-host $webpartmanager.WebParts[$i].title  
      # Check for the name of required web part    
      if($webpartmanager.WebParts[$i].title -eq "Content Query Web Part")    
      {    
           #Get reference to the web part   
           $wp = $webpartmanager.WebParts[$i];   
           write-host $wp.title " " $i  
           # If there is any existing filter, copy it  
           write-host $wp.AuthorizationFilter  
           # In the filter (empty: ;;;;;;), first two semicolons: individual users as target audience; second two semicolons: distribution list; last two semicolons: can be replaced to include sharepoint groups    
           # e.g. "174e7e9d-ff39-4856-85a6-9247b02e59fb,124f1234-3998-4b54-83d1-abc4048fb9b4;;;;"  
           ### Optionally perform direct update while in for loop  
           # Other properties e.g. chrome property   
           #$wp.ChromeType="TitleAndBorder";   
           # Save changes to webpartmanager. This step is necessary. Otherwise changes wont be reflected   
           #$webpartmanager.SaveChanges($wp);   
  }    
  }    
 ### Uncomment the lines below to perform the update  
 #$wp = $webpartmanager.WebParts[26];  
 #write-host "begin update: " $wp.Title  
 #$wp.AuthorizationFilter = "174e7e9d-ff39-4856-85a6-9247b02e59fb,124f1234-3998-4b54-83d1-abc4048fb9b4,3a87dc31-9067-4996-b4c2-5efc6ff3eab7,68d2a840-bdbb-44ee-aacd-395b5551c473,7add71c2-dbea-4218-b8ff-f6b112f225e4,577550be-616e-41cd-90a4-493c030ddd72,9f113155-7c70-4d18-9417-851d82ba8b6a,c664006b-ec7f-4798-9acc-c48766be68a8,e26f7ece-615c-474d-9db9-0f60953e113a,ee912564-4f77-43c4-aced-55d387bc4e8e,51d2b9df-7ca3-42ad-a307-f9fdf28fe417,59500291-5912-47c0-b6a2-9c9adf24f2da;;;;";  
 #$webpartmanager.SaveChanges($wp);  
 #write-host "saving webpart target audience done...";  
 ### Uncomment the lines below to check in and Publish the page   
 #$page.CheckIn("Update Audience(batch powershell)")   
 #$page.Publish("Update Audience batch powershell)")   
 #$SPWeb.Update();    
 # Dispose SPWeb object   
 $SPWeb.Dispose();