Codice PHP:
	
if ( ! function_exists('auto_link'))
{
    function auto_link($str, $type = 'both', $popup = FALSE)
    {
        if ($type != 'email')
        {
            if (preg_match_all("#(^|\s|\()((http(s?)://)|(www\.))(\w+[^\s\)\<]+)#i", $str, $matches))
            {
                $pop = ($popup == TRUE) ? " target=\"_blank\" " : "";
                for ($i = 0; $i < count($matches['0']); $i++)
                {
                    $period = '';
                    if (preg_match("|\.$|", $matches['6'][$i]))
                    {
                        $period = '.';
                        $matches['6'][$i] = substr($matches['6'][$i], 0, -1);
                    }
                    $str = str_replace($matches['0'][$i],
                                        $matches['1'][$i].'<a href="http'.
                                        $matches['4'][$i].'://'.
                                        $matches['5'][$i].
                                        $matches['6'][$i].'"'.$pop.'>http'.
                                        $matches['4'][$i].'://'.
                                        $matches['5'][$i].
                                        $matches['6'][$i].'</a>'.
                                        $period, $str);
                }
            }
        }
        if ($type != 'url')
        {
            if (preg_match_all("/([a-zA-Z0-9_\.\-\+]+)@([a-zA-Z0-9\-]+)\.([a-zA-Z0-9\-\.]*)/i", $str, $matches))
            {
                for ($i = 0; $i < count($matches['0']); $i++)
                {
                    $period = '';
                    if (preg_match("|\.$|", $matches['3'][$i]))
                    {
                        $period = '.';
                        $matches['3'][$i] = substr($matches['3'][$i], 0, -1);
                    }
                    $str = str_replace($matches['0'][$i], safe_mailto($matches['1'][$i].'@'.$matches['2'][$i].'.'.$matches['3'][$i]).$period, $str);
                }
            }
        }
        return $str;
    }
} 
 
codice preso dall'helper url di codeigniter, se lanci la funzione auto_link() su di un testo questa trasforma tutti i link e gli indirizzi email in link cliccabili... vedi se fa' al caso tuo, mi sembra un ottimo punto di partenza...