Use a <location> element in your web.config for the two pages (help/contact). Inside the <location> element, set the <authorization> element to allow access to all users.
A sample of this might look as follows
<!-- normal system web content -->
...
</system.web>
<location path="contactus.aspx">
<system.web>
<authorization>
<allow users="*" />
</authorization>
</system.web>
</location>
...
</configuration>
Dave