My parents read it to me when I was younger. I haven't read it since then, but I remember it in broad strokes. I don't have any desire to re-read it before the movie comes out either, I prefer to have it fill in what I have forgotten to having the book fresh in memory. If do there will be the inevitable and disrupting "why did they change that detail? Why did they leave that out!?".
Haven't watched the trailer. I generally don't watch trailers for movies I know I'm gonna watch anyway. Knowing a little about a movie before you watch it rarely spoils it, on the contrary, it can make it a lot easier and somewhat more enjoyable to watch. But I already know the basic premise, and I don't need to be sold on it any further, so all it's gonna do is get me more pumped up, and I prefer to save that pumped up-ness for when it's actually out ^^
On a related note. I actually sat down and read through Lord of the Rings this last summer. It blew me away. Seriously, I kind of expected just another fantasy novel, but I was obviously wrong. It's amazing, I can't believe it took me that long to read it, even for a guy who almost never reads. I almost thought it would make me think less of the movie, but on the contrary, it just made me appreciate them more. I guess what it all adds up to is: Lord of the Rings is awesome.