$re = '/<a\s*href="([^"]*)"[^>]*>(.*)<\/a>/';
$str = '<a href="http://www.kimoco.it/prodotti/mazzette/" title="Mazzette colori"><img src="http://www.kimoco.it/wp-content/uploads/2013/06/ico-mazzette-colori.png" alt="mazzetta colori" width="125" height="92" /></a>
<a href="" title="Mazzette colori">CIAO</a>
<a href="mailto:<U+2028>info@kimoco.it"><U+2028>info@kimoco.it</a>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php