Falcon 9 is SpaceX's flagship rocket , and a great leap forward for President Obama's plans to diversify  the space industry  (video of launch below). The vehicle will help ferry cargo up to the International Space Station in the years between NASA's retirement of the Space Shuttles and developing a new heavy-lift launch capability of its own. It's 55 meters tall, and powered by nine of the same Merlin engines that SpaceX has been developing for years to power its fleet. These specs make the vehicle a promising medium-heavy lift rocket, capable of carrying payloads that measure up to 11 meters tall. And they're also good enough that one day the rocket may be able to be human cargo-ratable, turning it into a serious alternative launch system for NASA to consider  for the manned space missions.
There is a fantastic shot of the second stage booster disconnecting at 3:27 into the video.
Here's a time-lapse of the Falcon 9 being moved to the launch pad in preparation for the takeoff.
Via the Commercial Spaceflight Federation:
Washington, D.C., June 4, 2010 – Space industry leaders, astronauts, and the Commercial Spaceflight Federation are issuing the following statements following today’s launch of the Falcon 9 vehicle:
Bretton Alexander, President of the Commercial Spaceflight Federation:
“Today is a historic day for SpaceX. The Falcon 9 rocket rising into the sky was carrying the hopes and dreams of the hundreds of engineers who worked on this new project. And I know that thousands of well-wishers across the country were cheering that rocket on. For a brand-new rocket to accomplish this much on its first mission is truly impressive, given the historical difficulties of first flights.”
Mark Sirangelo, Chairman of Sierra Nevada Corporation Space Systems and Chairman of the Commercial Spaceflight Federation:
"Congratulations to Elon Musk and everyone working at SpaceX. The broader commercial space community has received a fantastic piece of good news today."
Russell "Rusty" Schweickart, former Apollo 9 astronaut:
"As a former Apollo astronaut, I think it's safe to say that SpaceX and the other commercial developers embody the 21st century version of the Apollo frontier spirit. It's enormously gratifying to see them succeed today.”
Frank DiBello, President and CEO of Space Florida:
“This is another giant leap forward on the path of commercial spaceflight. Florida's aerospace workforce can take special pride that SpaceX's launch happened right here at Cape Canaveral. This success means more jobs for Florida and Floridians, and this success also means a major new force in the evolution of a vibrant commercial space capability for the nation."
Dr. Peter H. Diamandis, Chairman of the X PRIZE Foundation:
“In President Barack Obama's new plan for NASA, a new player has taken center stage – American capitalism and entrepreneurship – and today's SpaceX launch strengthens my hope that commercial space companies will at long last remove the cost barrier that slows our exploration of the solar system."
Eric Anderson, Chairman and CEO of Space Adventures:
“It's a tremendous accomplishment for SpaceX to succeed on the first try for Falcon 9. There's a bright future ahead for the commercial spaceflight industry and today was a big day."
Byron Lichtenberg, former Space Shuttle astronaut:
“I expect that there will be a lot more astronauts in the future because of today's success. Lower cost launches means more flights, which means more astronauts. We've only had 500 astronauts in the history of the Space Age, but I hope to see thousands more in the decades to come."
The Planetary Society, the world’s largest space advocacy organization by membership:
“With this success for the commercial spaceflight industry, the United States is better positioned to ramp up its ambitions for exploring the solar system. The proposal to refocus NASA's human spaceflight program beyond low-Earth orbit now looks more achievable, as this flight demonstrated that commercial rockets may soon be ready to carry supplies and, we hope, astronauts to the International Space Station.”
Dr. Alan Stern, former NASA Associate Administrator for Science and now Associate Vice President at the Southwest Research Institute:
"Congratulations to SpaceX on this phenomenal achievement. Falcon 9 and other commercial rockets will allow America to more quickly supplant Russian rides to orbit for our astronauts, to encourage the development of space tourism and other businesses in low Earth orbit, and to more economically transport crew and cargo to orbit so that we can afford human exploration of new worlds within NASA's budget."