It has finally arrived, as said in the Official blog post (
http://windowsliveagents.spaces.live.com/blog/cns!5BCD45E519E07634!584.entry). I'm downloading the SDK right now, and the PHI site (
http://phi.agents.live.com/) is up too!
Go grab the SDK now, and MSDN doc. Is online since last week.
Looks that this night I won't get too much sleep...