Directory listing can be added by using an asp page. Instructions to do this can be found on Microsoft's Support Site by following this link:

http://support.microsoft.com/kb/224364

You can also do directory listing via the web.config with the below code. You will specify the folder name based on the /web/content directory being the root. So if you have /web/content/mynewfolder the lines will look like below:

<configuration>

<location path="mynewfolder">
   <system.webServer>
    <directoryBrowse enabled="true" />
   </system.webServer>

</location>
</configuration>