System administrators will almost always set the default home page for the browser to the corporate website or intranet when building a machine. This is just a small registry hack that will set the home page for IE6 or IE7. You could probably use this in a logon script to set to home page on all users when they login to the network.
There is an easier and less intrusive way: A registry hack. Sure, you could use group policy. But why? Lets get geeky!
[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"Start Page"="http://www.fortypoundhead.com/"