I'm confused about the Visa's....do I need one for each country?
 

This may be a stupid question but here goes......
We will be in Thailand, Laos, Cambodia and China (Hong Kong on the way home)
I know we need a visa in Cambodia...do we need one for the other countries also and if so what is the easiest way to get them.

I've heard of people obtaining them before them leave through an email website?

First, you need to state your nationality. Not everybody here is US Citizen.

But assuming you are one, you don't need a visa for Thailand and Hong Kong. You can get visas upon arrivals for Laos and Cambodia.

If you're going to China proper (not just Hong Kong), you need to get a visa beforehand.

Here's a good page for such information:

travel.state.gov/travel/cis_pa_tw/cis/cis_1765.html

Jasper, rkkwan has given you good info.

Note that there are places where you get visa-free entry (Thailand and Hong Kong from your list) places where you can get a visa on arrival with payment and one or more passport photos (Laos and Cambodia) and places where you must have a visa in advance or they won't let you on the plane (china, not including Hong Kong and VN are examples of these).

Other things to know: many Asian countries require that your passport must have 6 mos. validity beyond when you intend to leave that country. Also, some countries require that you have two facing pages that are blank for the visa and entry and exit stamps (cambodia is an example of this requirement).

you can get an evisa for cambodia. very easy. this is what i did, and immigration was a breeze.

Yes, I am a U.S. citizen and thank you all for responding.

You've answered all the questions that I asked (and more!)