MIIS 2003 How To: Upgrading from IIFP to MIIS 2003
The MIIS (Microsoft Identity Integration Server) will be a very common name in Exchange Server 2007 environments, we'll use it between organizations to synchronize and maintain different directories.
So.. Microsoft has published an documentation about it. Here is the description: The MIIS 2003 How To document set provides discussions and recommended solutions for specific challenges that are encountered when using MIIS 2003.
For more information about MIIS, please go to the following link: http://www.microsoft.com/miis