Hi Mike,
If you want to use SPNego for ABAP for Web UI and NWBC then the following video should be helpfull:
Implementing Single Sign-On with Kerberos Part 2
You can have more informaton in the impelmentation guide http://help.sap.com/download/sapsso/secure_login_impl_guide_en.pdf chapter 4.7.5 Kerberos Authentication for HTML-Based User Interfaces Using SAP NetWeaver AS for ABAP with SPNego
KR
Valerie