Resources - Useful Books
Travel Guide Books:
If you've ever entered a bookstore (and I'm going out on a limb by assuming that you have) then you already know that there is a giant section devoted entirely to travel. I'm not sure how many different companies write travel guides, but most will be familiar with The Lonely Planet, Fodors, and Rick Steves, to name a few. The reason there are so many different guides is because they all cater to a different type of traveler - budget, solo, family, etc. They all give similar information but vary in how they present it; some have more pictures and less text, while others have lots of words and only a handful of photos. It's up to you to figure out what you like and what works for you, and instead of bankrupting yourself buying every guide for your desired destination try the library first. When you figure out which one you love then go ahead and buy it, but until then play the field and don't get monogamous until you're absolutely sure you've found 'the one'.
A general travel guide is useful for trip planning, and parts of it can be very helpful to have with you on vacation. The only problem is that those books are bulky and heavy - if you have an e-reader then you can load up on as many as you'd like, but if you're the old fashioned type then think long and hard about if you want to drag that book around with you. Photocopy key pages, or (gasp!) rip them out of the book if you want. It feels wrong but I promise you that your elementary school librarian won't tell on you. (Unless you took the book out of your child's school library... in which case please don't rip up the book.)
I have found this series to be very useful as each book is written by a local parent;
Fodors;
Around Paris with kids
Around London with kids
Around Rome with kids
Another series that is full of helpful hints is "Culture Smart! A Quick Guide to Customs and Etiquette." They have books for many different countries and give the kind of information that guide books often don't delve into - the nuances of the people and how to avoid embarassing cultural gaffes. Quite handy if you want to avoid insulting someone with a simple hand gesture!
Children's Books:
Although I haven't read or used all of these books, they come highly recommended from other sources. If you have read any helpful books not listed please contact me and I will add them to the list:
Children Just Like Me - Anabel and Barnabas Kindersley
Maps and Globes - Jack Knowlton
Italy Specific:
Rome with Kids: An insiders guide - J.M. Pasquesi
This is Rome - Miroslav Sasek
The Diary of Melanie Martin - Carol Weston
Ancient Rome: Monuments past and present - r.a. Staccioli