Microsoft Internal Solutions
Micorsoft IT has implemented several internal IAM solutions and here is a list of links.
Enabling Cross-Forest Identity Management with Microsoft Identity Integration Server 2003:
https://www.microsoft.com/technet/itsolutions/msit/deploy/cfimwiis.mspx
Ensuring Identity Consistency at Microsoft:
https://www.microsoft.com/technet/itsolutions/msit/security/ensidcon.mspx
Structured Active Directory Schema Management at Microsoft:
https://www.microsoft.com/technet/itsolutions/msit/deploy/adschemamgmt.mspx
Group Policy Object Infrastructure Management at Microsoft:
https://www.microsoft.com/technet/itsolutions/msit/security/grppolobjectmgmt.mspx
Managing Active Directory at Microsoft:
https://www.microsoft.com/technet/itsolutions/msit/valuecard/managead.mspx