I dont think it is a prob with httpd.conf as it works on the local machine. On linux the solution is relatively easy, you simply modify your hosts file located in /etc
add the I.P address of the local machine along with the name of your virtualsite
Example
-----------
192.168.0.1
www.mysite.com
In Windoze you would need to do the same in /windows/hosts
In the United Kingdom version of windows, the hosts file has the extension .SAM if this is the case with your computer then simply rename hosts.sam to hosts.
You should find this works...cheers