Eh. I read the book a number of years ago, and wasn't impressed enough to make it a high priority to continue with the series. The movie's slightly less impressive than that.
It's a dark fantasy set on a parallel Earth, where a plucky young girl, Lyra, finds herself in great danger, pursued by an oppressive organization represented by the coldly beautiful, yet evil, Mrs. Coulter. There are talking animals, and the special effects seem good.
The movie brightens up the book's darkness quite a bit, notably by cutting off the grim ending. Sam Elliot shows up, looking and sounding just about exactly the same as he did in The Big Lebowski, a movie that was a lot more fun.