If you're traveling outside the United States in 2009, here are two pieces of advice: Get or renew your passport now, and think twice before planning a car trip to Mexico or Canada in June. That's when we may see the biggest change ever for Western Hemisphere travel. Starting June 1 (unless Congress changes the deadline), Americans will need to show a passport, a passport card or other special document to return to the United States by land or sea from Mexico and Canada.