I'm currently reading the book by Stephen King as well as watching the series on TV (Mondays CBS).
Everything is so compleely different between the two. So different that after the first episode hubby decided that he didn't want to even watch the series.
That's how it always is with a book adapted to a movie or series. Especially Stephen King stories. I think I've seen every book turned movie and none have made the transition well. The one I felt was close was Dreamcatcher, that is close until the very very end. Other than that, they never follow the book as well.
Reading a book just transports you into whatever it is you're reading, and as the reader you put your interpretation on things. You're engrossed in the book and usually hate to put it down until you find out what happens next - at least that's the way it is with me. I can stay up all night just to finish a great book. I think with a movie, however, the readers interpretation is replaced by the writers interpretation let along trying to fit the story into a several hour flick.
With the TV version of the Dome - it is utterly and completly different from the book. Almost every character is different. The main character Barbie in the book is innocent, in the TV version, the show starts out with him burying someone. The police chief in the book is not part of the illegal dealings with the Selectman, in the TV version he is involved in some way. The person appointed chief is different, well ... you get the picture. If I was to write out all the differences, I'd be here all night - sufice it to say they are really two separate stories.
I love the book (not hard to imagine since I am a Stephen King constant reader). I also, love the series. You just have to go into it knowing that it will be different, and different isn't always bad. I think that Stephen King explains it very well on his website here. I assume he was getting lots of emails and posts about the differences, so put out the letter/statement. That being said, I'm happy that the series was picked up for a 2nd season, and can't wait to be surprised with how things pan out in the TV version of the story.
If you haven't been watching it and want to catch up, you can stream the episodes at Amazon.com and probably on CBS too.