There won't be an official beta this week after all; Rimon wants to review the code and docs over the weekend before we take that step.
However, as an unofficial beta, Spyce 2.0 is available from subversion:
svn co http://svn-hosting.com/svn/spyce/trunk/spyce
The featureset is solid at this point. If you start playing around now, you won't get burned by changes of that sort. You may well find bugs, of course, which I'll fix as soon as I can.
The docs are up here, including a pretty good introduction as to Why Spyce 2.0 Rocks, if I say so myself. (That is, I say the intro is pretty good. But also that Spyce2 rocks, for that matter.) The to-do demo and an enhanced version of the chatbox demo are both included.
Update: forgot a link to the changelog.