that will work, but it will rely on the user having a default email program setup, and they will still have to manually send the message from their mail client...
the simplest of php webforms may look something like this
<?php
$to = "you@example.com";
$subject = "Mail from Website";
if (!isset($_POST['submit'])) { ?>
<form method="POST">
Enter your name: <input type="text" name="name"><br />
<input type="submit" name="submit" value="Email Me">
</form>
<?php
} else { //form posted
$message = "Your form was submitted by " . $_POST['name'] . " on " date("r");
mail($to, $subject, $message, "From: $to");
echo "Your message was sent!!";
}
?>
this will use php to process the form contents and then use the webserver itself to send a message behind the scenes from the visitor.
Some extra stuff you may wanna research for the form processing is error checking and ensuring all the fields were filled out.