This is an interesting article.
For people migrating from Windows to Linux, the Apache Web server is entirely different world from Microsoft Internet Information Server. Apache can be alienating to IIS / Windows administrators, because migrating to Apache is more than just copying files.
The IIS to Apache migration process needs to be handled with the same care and perspective as the process of migrating desktops and their attendant applications. In some cases, IIS to Apache may be even more difficult and may have a larger impact on users and administrators.
In this article, author talk about the process of migrating a site from IIS to Apache, with Red Hat Linux as the specific target.