Yes, in the books, Gran dies early on.
Seriously, read the books. It does give a whole new twist to the series if you know some of the things in there.
Some of the (not so very spoilery, esp. if you've watched all the eps) differences so far.
Tara and Lafayette (and to a certain point, Jason) are not as major characters. Tara certainly doesn't have near as much personality, and Lafayette is much more flaming, and not a drug dealer.
Nothing happens btwn Tara and Sam.
Jason does not take V.
There's a lot less sex (it's all from Sookie's viewpoint, so the only sex we see is what she's directly involved in).
The Bellefleurs are much more frequent characters (Andy Bellefleur and his sister and grandmother).
No Bubba on the show yet (you won't get this unless you read the books!)