State Machine Workflows

http://www.codeproject.com/KB/WF/JumpStartMF.aspx

http://msdn.microsoft.com/en-us/library/ms734766(v=VS.90).aspx

http://visualstudiogallery.msdn.microsoft.com/en-us/7fe6f504-a58d-456e-8f55-e64bddc81a41

SharePoint Power Pack for UI Developers

http://www.sharepointdesignerstepbystep.com/default.aspx

Authentications

20 steps to get together Windows Authentication, Silverlight and WCF service

http://rouslan.com/2009/03/20-steps-to-get-together-windows-authentication-silverlight-and-wcf-service/

LDAP

http://blog.algoworks.com/archives/tag/openldap-and-ldapsoft-admin-tools 

NTLM

http://en.wikipedia.org/wiki/NTLM

Kerberos

http://en.wikipedia.org/wiki/Kerberos_(protocol)