3200 Phaeton looks like an ordinary asteroid but its orbit is identical with that of the Geminid meteors. Since meteors are assumed to be cometary debris, this may indicate than Phaeton is an extinct comet. Adonis and 2201 Oljato are two more asteroids considered to be possible extinct comets. Web Sites Devoted To Meteoritics Bill Arnett at the University of Arizona offers a number of web pages about meteoritics and small bodies in the solar system. Small Bodies introduces the subject and talks about the differences among comets, asteroids, and meteorites.
Asteroids talks about asteroids in general.
Comets talks about comets in general. Comet Halley talks about one of the most famous periodic comets in history. Meteorites introduces basic meteorite facts. SL9 discusses the recent breakup and impact of Comet Shoemaker-Levy 9 onto Jupiter. Each of Arnett's pages provides links to other sites with information about small bodies.