New travel document requirements will affect people travelling from the USA to Canada for the Olympics. Generally a valid passport should do the trick as well as special WHTI travel documents. If you are not clear on requirements you should read this and contact authorities to make sure you won't have problems returning to the US after the Olympics:
Returning to the U.S. after the Vancouver 2010 Olympic Winter Games Vancouver is expected to be a popular destination for U.S. citizens during the Vancouver 2010 Olympic Winter Games. Under the Western Hemisphere Travel Initiative (WHTI), U.S. citizens entering the the U.S. by air, land or sea from Vancouver or elsewhere in Canada must have a WHTI-approved travel document. Please allow several weeks for new document application and processing before leaving for Vancouver.
Arriving in the U.S. by Air
When returning home from Vancouver by plane you are required to present a U.S. passport, with these exceptions.
Entering the U.S. by Land
If you are a U.S. citizen driving, taking a bus or train back from Vancouver into the U.S., you are required to present a U.S. passport, U.S. passport card, enhanced driver’s license (EDL) or Trusted Traveler Program card. Some travelers may be part of the WHTI Special Groups in which case travel document requirements may be different.
Traveling to the U.S. by Sea
Travelers taking a ferry or small boat back to the U.S. from the Vancouver area must have a U.S. passport, U.S. passport card, enhanced driver’s license (EDL) or Trusted Traveler Program card. Some travelers may be part of the WHTI Special Groups in which case travel document requirements may be different.
The above information is for U.S. citizens on their way home from Vancouver or another destination in Canada. Canadian and Mexican citizens should access the appropriate WHTI information by clicking country of citizenship on the map on the home page.
Please allow four to six weeks to process your WHTI-approved travel document.
http://www.cbp.gov/xp/cgov/travel/
