If you travel internationally, you ought to check out the U.S. State Department’s free “Smart Traveler” app:
This is a great app for understanding Visa requirements, travel concerns, and other information on dozens and dozens of countries.
One small concern is that the language regarding travel warnings can be a bit over protective, particularly when it comes to Middle East or African countries:
But the app is full of useful info including maps:
This is a list of information available for each country:
Below, entry requirements for Canada…
You can see the app in the App Store, or by clicking here: Smart Traveler
Compatible with iPhone, iPod touch, and iPad. Requires iOS 4.0 or later