Hello,
I was checking the marketplace and found extensions for LDAP/Active Directory (https://www.magentocommerce.com/magento-connect/ldap-account-login-as-administrator.html and https://www.magentocommerce.com/magento-connect/diva-cloud-admin-ldap-auth-1.html) for administrators. However, I could not find extensions for LDAP/Active Directory for users. Does one exist? Thanks in advance!