Today, Elon Musk revealed his concept of how to get to Mars and beyond - the Interplanetary Transport System (ITS). He would like to send 100 people on an 80-150 day trip to the Red Planet. The BFS rocket will have a 12m booster and the spaceship will measure 17m. The stack will 122m tall. The booster will produce 127,800 kN (28,730,00 lb-f) of thrust and, of course, will return home. After landing, a propellant tanker will be loaded and the booster will send it to meet-up with, and fuel, the spaceship. The tanker then returns to Earth and the spaceship is off to Mars.
You can find the entire presentation on YouTube, but here is a summary video. The Next Big Future blog has a more lengthy summary.
Here is a pretty artist's conception of the ITS spaceship with its solar panels deployed. If you click through to Flickr, you will find more illustrations and photos of the recent test of the methane-powered Raptor engine.
Now, please tell me they will release a flying model of the BFS!