New Horizons must first be aimed at Pluto (and it's companion planet Charon; apparently NASA has officially stopped calling it a "moon") in order to get photographs and other data during the flyby. Closest point of approach to Pluto will be at 4:49am pdt, but it will continue photographing and collecting data on Pluto for at least several hours after the flyby. Then New Horizons will realign itself to aim its antenna back toward earth. It will first send a short ping to tell the mission team that the spacecraft made it through the Pluto system without mishap, and that the data was collected and is safely in NH's memory banks. This ping will take about four and a half hours to travel from Pluto back to Earth at the speed of light.
Then New Horizons will begin transmitting its preliminary data package. These will include low resolution (about the quality of a JPEG) images of Pluto and Charon during the flyby. Due to the highly attenuated signal crossing some three billion kilometers of interplanetary space, the baud rate of the transmissions will be maddeningly slow. Once received on earth they must be processed and analyzed.
Wednesday (15 July) at noon pdt, NASA will hold a press conference and release the first series of low resolution photos. This is the first new NASA press conference for this mission that will have any real information in it. High resolution photos are forthcoming, but will take about nine months to arrive.