There is a Shut Down Wall St. page linked from the front page of the Socialist Party USA. Strangely, as of this time, I have not found other Socialist Parties commenting about the Occupy Wall Street protest, as I would have expected.
They have a very short statement (“The Socialist Party USA supports the mobilizations to occupy Wall St. in New York and various cities across the US and encourages our locals to take part in these actions.”), a livestream from globalrevolution at livestream.com, a link to www.occupywallst.org, “Actions in other Locations:
http://occupytogether.org/” and links to protests in LA, Philadelphia and Boston, with contact information including facebook, email, and twitter.

I don’t think the bolshevik socialists will be able to get much traction with the general assemblies. No one seems interested in their vangaurdism. Their fixation on “leaders”. It is unfortuante that th Leninists are the only Left left in the US. They are sectarian cultlettes.
I think it is still early days w/ the Occupy… movement. But it does make me rest easier that the bolshies are so disillusioned with the movement.
The SEP (Socialist Equality Party) was there early talking to the örganizers” if they can be called that. You can read many articles on the protests at wsws.org. http://www.wsws.org/articles/2011/sep2011/wall-s26.shtml. There is a philisophy, of “no politics” among the crowd which is absurd if in fact they want the change they are demanding. The building of an independent party of the working class apart from the Democrats or unions is what is necessary. Otherwise as we see now, the Stalinist unions (who betray the rank and file in every instance), and middle class petty liberals and ex-left radicals, will try to control the movement leading them finally toward the Democrats and the dead end of the capitalist system.
This “action” took a lot of people by surprise, including yours truly. I’m not surprised that the “Socialists” and “Communists” would be slow to respond. I spent a week being mildly annoyed about all the internet commotion surrounding this “action” myself.
Ultimately, the organized left will likely latch on just at the moment when it’s about to collapse, if recent history is a reliable predictor.
Finally, I just don’t think the life conditions in the U.S.A. are similar enough to those in the Arab world for a “copy cat” movement to succeed here. We need different strategy and tactics, I think.
Found another one:
http://www.workers.org/2011/us/wall_street_0929