Currently, the lite.facebook.com link doesn't go anywhere and the invites have disappeared again, but just a few days ago, at least this Twitter user got to see it in action (hat tip to MG Siegler for finding this).
Attack on Twitter?
It is interesting to see that Facebook is working on this now, especially given that it only announced the acquisition of FriendFeed yesterday. If these screenshots turn out to be true, then this would be a full-force attack on Twitter. FriendFeed was often heralded as a potential challenger for Twitter, though it never quite got the mainstream traction to fulfill this promise.
Earlier this year, Louis Gray argued that in order to succeed, FriendFeed would have to offer a simplified version of itself. Now that FriendFeed is part of Facebook, maybe the FriendFeed team will get a chance to do just this.
Overall, stripping down Facebook's interface to the bare essentials doesn't seem like such a bad idea. The current interface is getting rather cluttered and if Facebook really wants to emphasize the stream, this is definitely a step in the right direction.