Miles Consulting Group - Implement and fully utilize and maximize the capabilities within Active Directory. IT environments will realize improved security, easily manageable user accounts and groups, and increased operational efficiencies. - http://www.milesconsultingcorp.com/Active-Directory.aspx
Dovestones Software - Utilities to bulk import/export users and contacts into Active Directory. - http://www.dovestones.com
NetPro - Security, performance, availability and change auditing solutions for Active Directory. - http://www.netpro.com/solutions/activedirectory.cfm
tools4ever - Flexibility of scripting without requiring the effort or knowledge. Perform advanced user management tasks for NT and Active Directory such as automated user creation, mass assignment of Microsoft Exchange mail boxes, or set folder permissions. - http://www.tools4ever.com/products/user-management-resource-administrator/
LabMice.net: Active Directory Resources - Directory of articles, whitepapers, book reviews, tutorials, FAQs and additional links related to Active Directory, LDAP. Group Policies, deployment, and ADSI. - http://www.labmice.net/activedirectory/
Nigl Network Solutions - Development of system-tools for Windows environments. - http://www.nns.at/
ADS Support.net - Free dedicated AD support, FAQ's, information and forums - http://www.adssupport.net/
ActiveDir.org - Home of the "Active Directory Discussions" mailing list and general resource site. - http://www.activedir.org/