Passports and VisasYou probably already know you need to have a valid passport for visiting China. But you also need an appropriate visa. Visas are issued by the Chinese embassy or consulate general serving your area. You can deal in person with the embassy or consulate, or you can ask your travel agent to manage the process for you. Special visa agents can also arrange your visa for you (for agents, google search "get china visa") but these services will cost extra on top of the $50 visa itself.
Health ConcernsYou've heard about SARS and Avian Flu. You're concerned, but there's no reason to cancel your trip to China! Taking precautions while visiting any new place is a good idea and finding out the latest on what's happening in the area is the smart thing to do. The US Center for Disease Control doesn't require any vaccinations before you go to China, but they do make some recommendations. There are also some basic items you'll want to take with you just in case you have a run-in with a bad dumpling!
Money MattersWhen I first started traveling, the travelers' check was THE way to carry money around. Now with the prevalence of ATMs and credit cards, there are more convenient ways to make your purchases. Having a little advance notice of the denomination of the Chinese currency can also help you prepare for your trip. These links will help you understand what you'll need to prepare with regard to your wallet.
Traveling with Small ChildrenThe anticipation is probably worse than the reality of the trip. Traveling with children is stressful. But you can alleviate some of that stress by bringing what you need and buying the rest. Being prepared is most of the battle when you've got kids in tow, so make it easy on yourself. Knowing what kinds of activities are available for the little ones when they get bored with temples and monuments is also helpful. Check out kids' activities in Shanghai for examples.
Planning Your ItineraryNow that you've got the mundane bits out of the way, it's time to focus on planning your itinerary. Is it bright lights and big cities you're into? Then you may want to start out in Shanghai. Perhaps it's China's long history, best exemplified by the Great Wall you're after exploring. Whatever you decide, you'll exhaust your time for planning before you exhaust the possibilities. Enjoy!
PackingThe best advice I give my friends who come to China is this: pack light! There is so much shopping to do, most travelers have no problem filling up their suitcases on the way home. So don't bring too much with you - you really don't need that much.
That said, there are a few essentials you should have along with you. As the saying goes, if you don't want it to rain, bring an umbrella. My theory is be prepared on the health front and bring along a first aid kit so you don't have to worry about minor illnesses should they pop up. If you have it with you, hopefully you won't need it.