The CNN Center offers an excellent tour. Details can be found at http://www.cnn.com/tour/. I haven't done it myself but it hear it's very interesting.
Also, just to put a plug in, i would invite you to visit thr Georgia Aquarium direct across Centenial Park from CNN. http://www.georgiaaquarium.org/
And next door to the aquarium is the World of Coca-Cola. Lots of history and you can sample their beverages from all over the world.
Enjoy your stay! about 5 years ago
You don't have to book tickets in advance, just show up and buy them. I think tours end before 5, though.
Also, a little factoid: to tour the CNN center, you have to ride the world's longest freestanding escalator to get to the 8th story where the tour begins. about 5 years ago