From the Daily News:
Big Brother is watching -- and solving crime.
The NYPD's network of silent sentries -- cameras posted on lampposts across the five boroughs -- has provided evidence in hundreds of criminal cases and helped cops solve an array of major crimes.
The Argus cameras are housed below large white boxes, clearly marked with the NYPD insignia, and are set about 20 feet off the ground near a warning: "NYPD Area Under Surveillance."
The cameras, installed in 2006, have so far captured 349 images used to help investigators, police said.
In all, there are 315 cameras citywide, with the bulk of them (145) in Manhattan. Brooklyn has 75, Queens 60, The Bronx 22 and Staten Island 13.