A short CSS snippet that changes the styling of external links, email links and links to pdf documents.
/* external links */
a[href^="http://"]{
padding-right: 20px;
background: url(external.gif) no-repeat center right;
}
/* emails */
a[href^="mailto:"]{
padding-right: 20px;
background: url(email.png) no-repeat center right;
}
/* pdfs */
a[href$=".pdf"]{
padding-right: 20px;
background: url(pdf.png) no-repeat center right;