xq no usas la funcion del phpbb?
Código PHP:
function make_clickable($text)
{
$ret = ' ' . $text;
$ret = preg_replace("#(^|[\n ])([\w]+?://[^ \"\n\r\t<]*)#is", "\\1<a href=\"\\2\" target=\"_blank\">\\2</a>", $ret);
$ret = preg_replace("#(^|[\n ])((www|ftp)\.[^ \"\t\n\r<]*)#is", "\\1<a href=\"http://\\2\" target=\"_blank\">\\2</a>", $ret);
$ret = preg_replace("#(^|[\n ])([a-z0-9&\-_.]+?)@([\w\-]+\.([\w\-\.]+\.)*[\w]+)#i", "\\1<a href=\"mailto:\\2@\\3\">\\2@\\3</a>", $ret);
$ret = substr($ret, 1);
return($ret);
}