>>585
しょぼいですが、こんな感じです
if(ereg("http://",$done)){
$ldone = $done;
// URL
$urladd = mb_ereg_replace("[^0-9a-zA-Z\/:.]","",$ldone);
// LINK
$mdone = "<A HREF=\"".$urladd."\" target=\"_blank\">".$urladd."</A>\n";
$new .= mb_ereg_replace($urladd,$mdone,$done);
}