Great image from MSNBC PhotoBlog that tries to demonstrate how much space junk we have put into orbit around Earth.  I think the downside of this image is that the satellites aren't to scale.  If they were all this large, they would be running into each other all the time.

If you have Windows, you can see this high-res version with Microsoft HDView, but it doesn't work on a Mac.  I was able to see it with Parallels running on my MacBook.

A computer-generated artist's impression released by the European Space Agency (ESA) depicts an approximation of 12,000 objects in orbit around the Earth. A communications satellite belonging to US company Iridium collided with a defunct Russian military satellite on February 12, 2009. (ESA via AFP - Getty Images/)

Thanks Karen for sending in the link!