It's a completely awesome series. My 4th-grade teacher read the first three books in the series to my class, doing all the voices, and we couldn't get enough of it.

Disney did an adaptation of the books some years back, titled The Black Cauldron (which is the title of the second book, even though the movie is mostly about the first book. I don't pretend to understand Disney's thought process). Whatever you do, don't watch it!