Problem with output encoding in PHP mail form

[slot]

Hello, when some one send mail from the PHP Contact form with the capcha pic, in the mail box in some mail clients receive this "?" sign.
Can someone help me with changing the output encoding?

[slot]

How can i input $headers in that string:
mail("", 'Онлайн заявка от: '.$subject, $_REQUEST['product']."\n\n".$broi."\n\n".$message, "From: $from");

Thank you

[slot]

I fixed myself:
mail("adress@mymail.com", 'From: '.$subject, $send."<br />\r\n".'Adress: '.$message."\n\n", $headers);

:p :)