An hour or so ago Twitter started to buzz with word of arrests coming from the Occupy Wall Street event located around Zuccotti Park and Trinity Church. In watching live video stream NYPD seems to be pulling random people from the crowd and off the sidewalk and putting them into police vans. They are using mega phones and a large police presence to push the marchers out of the streets. Watch live stream from two sources on the street.http://www.livestream.com/globalrevolution 

It sounds like 15-20 people have been arrested so far although there are no official numbers from NYPD as of yet.

8:34 PM - 15 Sep 12 Rt_America @RT_America Tweeted

"Several protesters arrested in NYC tonight as Occupiers march before #OWS anniversary. Reports that NYCLU legal observer among arrested"

9:14 PM - 15 Sep 12 Dustin M. Slaughter @DustinSlaughter Tweeted

    "The police have effectively flushed people from #Zuccotti. Protesters have disbursed to a park five or six blocks away. #S17 #OWS"

For video from earlier this evening watch Occupy Eye http://www.ustream.tv/occupyeye 

EDITED: Sept. 16, 2012 

Related articles with a count of 25 arrests.

http://blogs.villagevoice.com/runninscared/2012/09/occupy_wall_str_57.php

http://online.wsj.com/article/SB10000872396390444517304577653820351290322.html?mod=googlenews_wsj

Link to 4 live video streams on one page.

http://occupypeace.blogspot.com/2012/09/ows-anniversary-ustreams.html

EDITED: Sept. 17, 2012 1:13pm times are eastern

Reports through twitter say 80-100 arrests today so far. Will confirm as soon as I can.

Police made 124 arrests by 12:15 pm, mainly for disorderly conduct when protestors impeded vehicular or pedestrian traffic, NYPD chief spokesman Paul Browne said. Browne also confirmed 43 arrests were made over the weekend, including for disorderly conduct, assault and resisting arrest,.

http://blogs.wsj.com/metropolis/2012/09/17/protesters-arrested-on-occupy-wall-street-anniversary/