If:
then you do not need a visa under the Visa Waiver Program.
For other member-countries of the Visa Waiver Program along with information on qualifying under it, see the US Department of State's site on the subject:
http://travel.state.gov/visa/temp/types/types_1262.html#2
If I am a resident of the US. Do I need a visa to go to Canada?
Yes US citizens need a visa.
Yes, you do need a visa.
Yes, US citizens need a visa to travel to Ireland.
Yes, US citizens need a visa to travel to London.
Yes, US citizens need a visa to travel to Uzbekistan.
Yes, US citizens need a visa to travel to Kazakhstan.
Yes, US citizens need a visa to travel to Russia.
Yes, US citizens need a visa to travel to Uzbekistan.
Yes, US citizens need a visa to visit Argentina.
Yes, US citizens need a visa to visit Kazakhstan.
Yes if you do not have any valid US Visa. No if you have a valid US Visa.