Should have added that you'll need to restart Apache to get any changes to work. Typically this has to be done as root. To restart Apache you can either HUP Apache's lowest PID or use the restart script. To HUP, run the following to get a list of all Apache PID's and HUP the lowest:
>ps ax | grep httpd
>kill -HUP <pid>
To use the restart script:
>/usr/local/apache/bin/apachectl restart
The apachectl file may be in a different location depending on your distribution and installation. HTH.
-geoff