On Monday April 30th, 2012, SpaceX will do a static launch test of their rocket propulsion system, called Falcon 9, in advance of their planned launch. The static launch, which is available for viewing here will start at 2:30pm EST with the actual static firing of the rocket boosters taking place at 3:00pm EST. The Firing, which will take place at SLC-40 at Cape Canaveral Air Force Base, is part of a full dress rehearsal for the real launch to take place shortly thereafter on May 7th.
The dress rehearsal will also have SpaceX engineers running through all countdown processes as though it were launch day. The exercise will end with all nine engines firing at full power for two seconds. If the test is successful, then SpaceX will launch a Dragon spacecraft into low-Earth orbit atop a Falcon 9 rocket. If that launch in May is successful, then the spacecraft will get the approval form NASA to dock with the International Space Station and the crew there will unload the cargo.
If the Dragon is found capable of doing it's job, SpaceX will then start to fulfill its Commercial Resupply Services (CRS) contract for NASA for at least 12 missions to carry cargo to and from the space station. Dragon and Falcon 9 were designed to carry astronauts but this mission will give them valuable experience.
SpaceX made history in December of 2010 by the first commercial company in history to send a spacecraft to orbit and return it safely to Earth.