Note: This article is old and may not be revised to reflect changes with the product terminology etc. This was written for WSS/MOSS 2007, Windows 2003 and IIS 6.
Change your existing host header in SharePoint ( WSS or MOSS 2007 )
Do you want to publish your SharePoint intranet or internet site to your users with a nice friendly url (or hostheader)?
This article can be also used if you want to rename your web application.