Saw the first two movies and then read the next three books! Couldn't put them down. For me, it's easier to read a book when I can visualize the characters. Azkaban was fair but I liked Goblet of fire and Order of the Phoenix.
Now, I have been going back to the first two and reading parts to see how they differ from the flicks.
I did the exact same thing. I did not really have any interest in the Harry Potter series until I saw the first two movies. My wife had started my neices and nephew on them, and I watched the Sorcerer's Stone on TV one night when I could not find anything else to watch. I was instantly and hopelessly hooked. After seeing the Chamber of Secrets, I read Azkaban & The Goblet then I doubled back to read the first two books. When the Order of the Phoenix came out I read that immediately too.
The Prisoner of Azkaban is supposed to be in theatres on June 4th. Check out www.azkaban.com
I've read bits of them here and there, just to make sure they're children friendly.
We have no problems with our child reading them (heck, kids reading is great!), but many in our church will not allow their children to read about witches and sourcery. Actually, I think they were deprived of an imagination during their childhood.