I just took a look at my functions_email.php file where I found this code
Code:
// set the reply-to address. If none set yet, then use Store's default email name/address.
// If sending from contact-us or tell-a-friend page, use the supplied info
$email_reply_to_address = ($email_reply_to_address) ? $email_reply_to_address : (in_array($module, array('contact_us', 'tell_a_friend')) ? $from_email_address : EMAIL_FROM);
$email_reply_to_name = ($email_reply_to_name) ? $email_reply_to_name : (in_array($module, array('contact_us', 'tell_a_friend')) ? $from_email_name : STORE_NAME);
$mail->AddReplyTo($email_reply_to_address, $email_reply_to_name);
Does this mean that my contact_us form should be using the customer's email address? Or do I have to customize this to make that happen?