Of course you can use the Visa Waiver Program to travel to the United States for up to 90 days if you hold a passport of one of the 35 visa-waived countries.
http://travel.state.gov/visa/temp/without/without_1990.html#countries ..
If you plan a flight you will need a prior approval (ESTA) by the U.S. Department of Homeland Security which can be obtained free of charge on their website.
http://www.cbp.gov/xp/cgov/travel/id_visa/esta/ ..
If you enter by a land border you will have to obtain a Form I-94W at the border for a fee of $6.00 which must be presented to the U.S. immigration officer who decides for how long you may stay. When you get back to Canada and you do not plan to re-enter the United States during the duration of your granted visa-waiwed stay, just turn back the green form to a U.S. border guard on a land border. If you fly the aircraft company will take care of that.
http://www.cbp.gov/xp/cgov/travel/id_visa/business_pleasure/vwp/i94_samples.xml ..
Just in case your travel plan changes and you do not plan to re-enter the U.S. but still have the green form in your passport please follow the instructions on the attached link.
http://london.usembassy.gov/dhs/cbp/i94.html ..