Implement FaceBook’s Meta Propertys Into ASP.NET Page

In Page Load event:

 

        // Support for FaceBook Social Meta Graph
        HtmlMeta meta = new HtmlMeta();        
        meta.Attributes.Add("property", "og:title");
        meta.Attributes.Add("content", "Title here");
        Page.Header.Controls.Add(meta);

        meta = new HtmlMeta();  
        meta.Attributes.Add("property", "og:description");
        meta.Attributes.Add("content", "This is the longer description");
        Page.Header.Controls.Add(meta);
        
        meta = new HtmlMeta();  
        meta.Attributes.Add("property", "og:image");
        meta.Attributes.Add("content", "http://www.yourdomain.com/path/to/thumb_image.jpg");
        Page.Header.Controls.Add(meta);      

How To Create A Custom Share Link (Images and URL Pointers)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">	
<head>		
<meta http-equiv="refresh" content="0;url=http://www.facebook.com/PSOklahoma?v=app_4949752878">		
<meta property="og:url" content="http://www.facebook.com/PSOklahoma?v=app_4949752878"/> 		
<meta property="og:image" content="http://test2009.psoklahoma.com/global/utilities/lib/images/content/FaceBook/PSOklahoma/icon_MakeAMatch.jpg"/> 		
<meta property="og:site_name" content="Make a Love Match this Valentine's Day. Each time you play  Public Service Co. of Oklahoma's card-matching game, a donation is made to help Oklahoma families in need."/> 		
<meta property="og:description" content="Play Public Service Co. of Oklahoma's Love Match game and help us donate up to $5,000 to the Light A Life Energy Fund. Light A Life helps Oklahoma families facing financial emergencies to heat their homes."/> 		
<title>Make a Love Match this Valentine's Day. Each time you play  Public Service Co. of Oklahoma's card-matching game, a donation is made to help Oklahoma families in need.  </title>		
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />	
</head>	
<body>
</body>	
</html>

Then to create the Share link point to this HTML file (above):
http://www.facebook.com/sharer.php?u=http://test2009.psoklahoma.com/FaceBook/PSO_MakeAMatchShare.html

More info here documenting the Open Graph Protocol.