<config>
    <modules>
        <Magentotutorial_Layoutviewer>
            <active>true</active>
            <codePool>local</codePool>
        </Magentotutorial_Layoutviewer>
    </modules>

    <global>
        <events>
            <controller_front_init_routers>
                <observers>

Have you installed the module into the "Magentotutorial" package and not the "Alanstormdotcom" one?

Have you cleared your cache?   (I seem to be having a really hard time clearing the cache!)

                    <Magentotutorial_layoutviewer_model_observer>
                        <type>singleton</type>
                        <class>Magentotutorial_Layoutviewer_Model_Observer</class>
                        <method>checkForLayoutDisplayRequest</method>
                    </Magentotutorial_layoutviewer_model_observer>
                </observers>
            </controller_front_init_routers>
        </events>
    </global>
</config>