From Guanjun’s blog:
“This is the Beijing National Stadium, also known as the bird’s nest, it will be the main track and field stadium for the 2008 Summer Olympics and will be host to the Opening and Closing ceremonies. It will seat 100.000 spectators during the Olympics in August 2008. After the games the number will be reduced to 80.000. The stadium is 330 metres long by 220 metres wide, and is 69.2 metres tall.” －from FunForever blog.