So I made a point to watch the shuttle launch with my eyes and have the camera sitting on a tripod with a remote in my hand to fire the camera. After a few minutes I decided to unmount my still camera and shoot some pictures of the distant dot up in the sky. Looking at a 100% crop of this shot, you can see the pair of solid rocket boosters disconnect from the orbiter (the plane) and external fuel tank (the orange tank). Those two bad boys provide 83% of the shuttle's lift power and disconnect once they get the shuttle up to 22 miles in orbit. Like the orbiter, these two rockets come back to earth and are reused. They'll jettison parachutes and land down in the ocean. On the other hand, the orange external fuel tank, when it's released, it'll fall back into the earth's atmosphere and burn up on reentry.
One thing I noticed, which you can tell from this picture, is that the SRBs burn orange while the ET and orbiter burn more white. Perhaps due to different rocket fuels?
Edit: Heard back from Stan about the various colors:
"The difference in color between the SRBs is the fuel. The main engines burn hydrogen, which gives a perfectly clear, minimally blue flame. The SRBs are this super toxic fuel that burns orange. They are also responsible for the popping noise they make; if you had a purely hydrogen powered rocket, such as the Soyuz or Atlas, you would barely hear (or see) anything. As a matter of fact you could stand a few hundred feet off a Soyuz launch pad and still survive - the SRB shockwaves would do very bad things to you."