I'm not sure how things are done in Wordpress or jQuery but your javascript function needs to be changed slightly I think and the code needs to be in the <head></head>
section ideally.
jQuery(document).ready(function($) {
$("#ajax-contact-form").submit( function( event ) {
/* Prevent the form actually submitting in standard manner */
event.preventDefault();
var str = $(this).serialize();
$.ajax({
type: "POST",
url: "/includes/contact-process.php",
data: str,
success: function(msg) {
// Message Sent? Show the 'Thank You' message and hide the form
if(msg == 'OK') {
result = '<div class="notification_ok">Your message has been sent. Thank you!</div>';
$("#fields").hide();
} else {
result = msg;
}
$('#note').html(result);
}
});
return false;
});
});
And, the path you need to use in your ajax function also needs to be changed - has been edited above. ( I got a 404 when trying just now )