External link icon

Download a suitable icon to use and ftp to the images directory of your template

The one I used was here:
http://commons.wikimedia.org/wiki/File:Icon_External_Link.png

Add the following code to your template.css file, or suitable css file:

a[href^="http://"] {background: url('../images/external.png') center right no-repeat;
padding-right: 13px;}
a[href^="https://"] {background: url('../images/external.png') center right no-repeat;
padding-right: 13px;}
a[href^="http://www.yourdomain.com"] {background: none;padding-right: 0;}

The last part will eliminate the icon for internal links.