As of June 1, 2009, US citizens returning to the US from Canada, Mexico or the Caribbean must present an official US Passport, Passport Card or other documents that verify US citizenship and identity. For more information, please see the WHTI web site.
It is the student's responsibility to obtain the necessary visas for foreign travel. The best place to obtain information is from web page of the country's embassy in Washington, DC. For a list of visa requirements and foreign embassies and diplomatic missions click here.
http://travel.state.gov/travel/tips/brochures/brochures_1229.html
Passports are issued by the US Department of State. You can apply in person at a US Post Office or by mail (renewals only, certain restrictions apply).Even if you're "just going to Canada or Mexico" you need a passport. Are you ready?