In PHP you can access the name of the page using:
<?php
$thisPage = $PHP_SELF . $QUERY_STRING;
?>
Then you can just take that variable and mail it to whatever email address a user wants. Obviously, you can't do this with an HTML page... only on a PHP script. Here's an example of the form you might want to use:
<Form action="MailToFriend.php">
Friend Email:<Input type=text name="friendEmail">
Your Email:<Input type=text name="yourEmail">
<Input type=hidden name="pageToSend" value="<?= $PHP_SELF . $QUERY_STRING ?>">
<Input type=submit value="Email Page!">
</Form>
Then in a script called MailToFriend.php you'll have the variables:
$friendEmail (email address for To🙂
$yourEmail (email address for From🙂
$pageToSend (location of page)
You can use PHP's mail() function to send the email out. See:
http://www.php.net/manual/en/function.mail.php