mageUz's answer does not follow best practices for keeping your Magento installation upgrade friendly. You should avoid editing cms.xml or any of the other base xml files.

A better way to do this would be the following in local.xml

    <cms_page>
        <reference name="left">
            <action method="setChild">
                <name>page_content_heading</name>
            </action>
        </reference>
        <reference name="content">
            <action method="unsetChild">
                <name>page_content_heading</name>
            </action>
        </reference>
    </cms_page>

Additionally, this can be done on a per page basis by putting this XML into the "Layout Update XML" field of the Design Tab, when editing pages from the admin. You would just omit the "cms_page" node, and instead just need the two "reference" xml nodes.