The International Space Station is a partnership of the US, Russian, European, Japanese, and Canadian Space Agencies. The station has been continuously human occupied since Nov 2, 2000. Orbiting 16 times per day at 17,500 miles per hour 250 miles above the ground, it passes over 90% of the world’s surface. When complete in 2010, it will weigh over 800,000 pounds and have a crew of 6 conducting research and preparing the way for future exploration to the moon and beyond.

The virtual tour uses Microsofts Photosynth. Just click the following link for the tour:
http://www.nasa.gov/externalflash/photosynth/index.html
(You'll be installing Microsoft Silverlight. It's small and fast.)

Its pretty interesting to see what the astronauts work in.