Couple things:
There are 4 books so far -- and the 4th book is basically half of what was originally going to be long 4th book. What we've been waiting for is the second half of that 4th book (which now becomes the 5th book).
That said, the series is awesome--probably one of the best ever written, certainly on par with Tolkien. The author certainly wasn't squeamish about killing good characters and letting evil characters get away with murder.
I can't wait for the series, everything I've read/heard/seen says that it's pretty spectacular. As far as cable shows, this and Walking Dead are the two I'm looking forward to over the coming months.