Here you can see ISS astronauts open the hatch and enter the Dragon.
Dragon was launched on the Falcon 9 rocket last week:
Liftoff from SpaceX on Vimeo.
The Falcon 9 launch vehicle carrying the Dragon spacecraft,
climbing from the launch pad. 5/22/12
Over the next few days the Dragon cargo (over 1000 pounds of supplies for the Space Station) will be emptied and return cargo (including experiments) will be put onto the craft for return to Earth next Thursday, May 31. The Dragon is scheduled to splash down that day in the Pacific Ocean, west of California.