Função para links

    function criaurl($string) {
        if (!is_string ($string))
            return false;

        // Verificando se existem links
        $string = ereg_replace("([[:alpha:]]+://|www.)[^<>[:space:]]+[[:alnum:]/]","<a href=\"\\0\">\\0</a>", $string);
        $string = ereg_replace("[a-zA-Z0-9_.]{1,30}@[a-zA-Z0-9_.]{1,30}.[[:alnum:]]{2,6}","<a href=\"mailto:\\0\">\\0</a>",$string);
        return $string;
    }