A simple mailer script with PHP Mailer to send mails via GMail. This does not include attachments but that's pretty easy to do once you get the mail working.

MailWithGMail.php

<?php 
    require('phpmailer/PHPMailerAutoload.php');

    //Taking data from a form
    $name = trim($_POST['con_name']);
    $email = trim($_POST['con_email']);
    $subject = trim($_POST['con_subject']);
    $message = trim($_POST['con_comment']);
    if($name != null && $email != null && $subject != null && $message != null){
		if(!filter_var($email, FILTER_VALIDATE_EMAIL)) 
		{
		    $signal = 'bad';
            $msg = 'Invalid email. Please check';
        }
        else{
            
            $mail = new PHPMailer;
            $mail ->isSMTP();
            $mail->Host = 'smtp.gmail.com';
            $mail->SMTPAuth = true;
            $mail->Username = 'username@gmail.com';
            $mail->Password = 'secret_password';
            $mail->SMTPSecure = 'tls';
            $mail->Port = 587;
            $mail->setFrom('username@company.com', 'FirstName LastName');
            $mail->addAddress('username@company.com');
            $mail->addReplyTo($email, $name);
            $mail->isHTML(true); //This allows for HTML tags so you can make your message as fancy as you want!
            $mail->Subject = $subject;
            $mail->Body    = 'Name: '.$name.' <br />Subject: '.$subject.' <br />Message: '.$message;
            
            if(!$mail->send()) {
                echo 'Message could not be sent.';
                echo 'Mailer Error: ' . $mail->ErrorInfo;
            } else {
                $signal = 'ok';
                $msg = 'Form submitted, We will reply ASAP!';
            }
        }
    }
    else{
        $signal = 'bad';
        $msg = 'Please fill in all the fields.';
    }
    $data = array(
        'signal' => $signal,
        'msg' => $msg
    );
    echo json_encode($data);
?>