function append_message(data) {
    fields = data[0].fields;
    message_str = fields.msg + '\nPosted by: <strong>'
                         + fields.posted_by + '</strong> on: '
                         + fields.timestamp;
    new_div = $('<div />').addClass('message').html(message_str);
    $('div#current_messages').append(new_div);
}

$('#msgform').submit(function() {
    $.post('/ajaxsubmit',
            {posted_by: $("input[name='posted_by']").val(),
               msg: $("textarea[name='msg']").val()},
            append_message, 'json');
     //For brevity, we're just going to assume this always works
     $("textarea[name='msg']").val('');
     return false;
});