Are you trying to host several different sites on the same sever without multiple I.Ps? Is so you must create virtual hosts for each site and then add the I.P address and host name to your etc/hosts file. A virtual host looks like this (add these to your httpd.conf file, change the domain names to your sites names, change the document root to the directories you wish:
<VirtualHost *>
ServerName
www.domain.com
DocumentRoot /www/domain
</VirtualHost>
<VirtualHost *>
ServerName
www.otherdomain.com
DocumentRoot /www/otherdomain
</VirtualHost>
After you have done that, add these names to your hosts file, and give them the same I.P. adress. For instance if the name is
www.domain.com and the i.p adress is 192.168.1.1, your hosts file would look like this
192.168.1.1
www.domain.com
192.168.1.1
www.theotherdomain.com
Apache will route to the proper site depending on the URL, you can host several different sites on the same box with the same I.P address. kind of like Host Headers in IIS.