Microsoft today released this doc (actually it"s a help file!) which is the .Net Passport SDK v2.1, (file dated 16th November 2001).
Changes include details for the following features :-
- User control over the sharing of personal data
Flexible-layout cobranding
Context-sensitive cobranding
Pane Help
Link Suppression
Inline Sign-In
Secure Sign-In
Mobile Passport
New user profile attributes
Shorter minimum password
Passport Manager
SDK Documentation.