Which countries participate in the Visa Waiver Program?

Citizens of the following countries can (under certain conditions) travel to the US without having to apply for a visa:

Andorra, Australia, Austria, Belgium, Brunei, Czech Republic, Denmark, Germany, Estonia, Finland, France, Great Britain, Hungary, Ireland, Iceland, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Monaco, New Zealand, Netherlands, Norway, Portugal, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland.