They are already in Central Park. From what I have read from the blogs they are there and there is going to be a standoff with the cops who are closing in now!
WABC reporting that the official numbers from the NYPD is only 100,000. And they confirmed that the same protesters are recircling the area.
Obviously there are some of them there, but it doesn't look like very many. Remember, these are the folks who couldn't get a Central Park rally permit 'cause they couldn't guarantee that they'd attract less than 75,000 ralliers.