This web page is an update from a Single Sign-On: Authenticating Linux WebAS ABAP in Windows AD which provides a description how to authenticate a SAP WebAS ABAP on Linux via Kerberos v5 and the SAP SNC adapter against a Windows 2003/2008 Active Directory and map their users to use Single Sign-On with the SAP GUI on Windows XP/7 clients.
German version available: http://www.realtech.com/wDeutsch/kontakt/contact-REALTECH-whitepaper-kerberos.php