I've done this before, but I don't have access at
this time to my home machine (where the setup examples
can be easily posted) so- here goes.

I found that in addition to editing the apache httpd.conf file, that a
host file entry (in /etc/hosts) was also required to achieve success.

Here are 4 links that should either get you started in the right
direction, or possibly even provide solution through their examples.

http://bobpeers.com/linux/apache_virtual_hosts.php
www.ubuntuproductivity.com/.../ubuntu-linux-virt\
ual-hosts-with-apache2/
linux.com/.../8202-how-to-set-up-apache-vi\
rtual-hosting
http://apptools.com/phptools/virtualhost.php