do not install an smtp server with wamp. spam-bots patrol the internet by the millions searching for insecure smtp servers they can use to use to send their spam from. that way you take the blame since the spam came from your server, not the spammers. you will get caught by your isp. you could be in big trouble since 99.999% of isp's do not allow you to host any websites with your isp account; and sending spam is an even bigger no-no.
the safest approach to be able to send and receive emails using your php scripts without the need for a server is to use phpmailer. it is very popular open source php mail framework.
[
phpmailer.sourceforge.net]
here is a sample of using phpmailer to use gmail.
$mail = new PHPMailer();
$mail->IsSMTP(); // send via SMTP
$mail->Host = "smtp.gmail.com"; // SMTP servers
$mail->SMTPAuth = true; // turn on SMTP authentication
$mail->Username = "myemail@gmail.com"; // SMTP username
$mail->Password = "mypassword"; // SMTP password