Code to change pre-set the e-mail field for a contactform7.
Remember to:
<?php if ( is_user_logged_in() ) : ?>
<?php global $current_user;
get_currentuserinfo();
?>
/* INSERT ContactForm7 ShortCode HERE */
<?php echo do_shortcode( 'CONTACT_FORM_7_SHORTCODE' ); ?>
<script> $(function() {
$('.contact-form-7-email-field-class-selector').val(<?php echo $current_user->email; ?>);
});
</script>
<?php endif; ?>