An interesting blog offers some random "I didn't know that" tidbits:
But what fate befell the iconic satellite? After 1,400 trips around the Earth, Sputnik burned up when it reentered the atmosphere in January of 1958 (just as it was supposed to). Over the years, the Soviet Union would go on to launch other satellites. Their very next one, Sputnik II, carried a live passenger -- a dog named "Laika."