"As far as books and other resources about Italy are concerned, I can suggest this:
As far as books about Rome, I saw you already listed my favorite: Seasons of Rome. What a delightful book! Paul Hofman also wrote "That Fine Italian Hand" which is also incredibly informative, though not as lightly written in tone as "The Seasons of Rome."
How about "The Incredible Book of Vatican Facts and Papal Curiousities - A Treasury of Trivia" by Nino Lo Bello?
Alright, now to novels: Micheal Dibdin has written a series of crime novels (my favorite one), known as the "Aurelio Zen Mysteries". They all take place in Italy, though not always Rome, and he has a very intriguing writing style and an interesting way with words.
Donna Leon has also written a series of crime novels playing in Italy. I've only read one book so far, which was not bad, though nothing outstanding. The serious starts out with "Death at La Fenice" continues with "Death in a Strange Country" etc.
Another crime novel series is by Iain Pears, the main character being Jonathan Argyll, an art scholar from England moving to Rome and getting involved in solving crimes, all of which revolve around art. A nice touch since you get to learn a little bit about art and the art world. The first book in the series is "The Raphael Affair" followed by "The Bernini Bust" (as far as I know the only one not taking place in Italy), "The Titian Committee" etc.
Then there is David Hewson's "A Season for the Dead" another crime novel playing entirely in Italy, if I remember correctly, all of it in Rome, and an entertaining read.
Of course, let's not forget Dan Brown's "Angels and Demons" which, although he is not one of my favorite authors, plays entirely in Rome and is especially wonderful for us tourists to read. The main character literally walks and searches the streets of Rome in an attempt to find clues to prevent a catastrophe. It takes us tourists right to the places we are coming - or have come - to visit.
Books about learning the language: The following list does not include books for travellers who simply want to learn some of the most common phrases to get by during their vacation. There are many available for that purpose and they are easy to find. The list is meant for those that are interested in learning the Italian language and are looking for comprehensive material.
Pimsleur's Comprehensive Italian, Levels 1-3 by Simon and Schuster
Absolutely the best. Very expensive, but well worth it. (Think "ebay.com"!) Contrary to most other courses I came across, it goes far beyond mindless repeating of what you hear a speaker say. New words are introduced syllable by syllable (backwards!) to make sure you really get the words, and you learn to make up your own sentences in a variety of ways that helps you grasp the grammar.
Vocabulearn by Penton Oversears, Inc.
Once you get the basics of Italian pronunciation and grammar, you'll need vocabulary! Vocabulearn is the best program for that.
It comes in three levels, sorted by word type, and includes common expressions as well. Unlike some other useless programm I tried, the vocabulary it is NOT in alphabethical order!
Complete Idiot's Guide to Learning Italian by Gabrielle Euvino
If you like a "light" approach with a little bit of humor, this book walks provides you all the basics.
Buongiorno Italia by EMC Corporation
A textbook with the traveller's needs in mind, includes lots of helpful tips and information about Italy.
Ciao by Carla Federici and Carla Larese Riga
Quite comprehensive and informative.
Italian with Ease by Assimil
One of my favorites! Italian and English next to each other as well as easy to understand Pronunciation help.
Readers and story books:
Diario della Studentessa Jean by Jean Farinelli
Entertaining short stories in diary format, easy to understand for beginners. No vocabulary or excercises, though.
Racconti Simpatici by Liliana Briefel
Cute and funny little short stories, rated "intermediate," although I would probably rate it at a beginner level. With vocabulary and excercises. Out of Print--Limited Availability.
L'Italia verso il Duemila by Ugo Skubikowski
Lots of information about Italy and Italian culture, from the origin of Pizza over the role of Soccer to politics and history. With vocabulary. It is supposed to be for intermediate students, but I would consider it intermediate to advanced.
Dagli Appennini alle Ande by M.A. Carino Biscaccia and M.R. Francomacoro
Story of the travels of an Italian boy, trying to find his mother in Argentina. Considered advanced material, but my rating would be intermediate. With vocabulary and excercises.
Un Amore Diverso by Claudio Manella
The story of a relationship, but not too cheesy. Vocabulary and exercises included. Intermediate level.
A break from traditional studying: Italian news, music, etc. bimonthly on CD or cassette on a subscription basis. Comes with transcription of the audio material and vocabulary; advertized to be for intermediate to advanced learners, but I'd say it leans towards the advanced level.