When travelling from Canada (with its nominal 120V, 60Hz supply) to anywhere outside of the Americas you'll always need a device which incorporates a transformer (rather than just a simple plug adapter) because the rest of the world uses supplies with nominal voltages between 220V and 240V. (Obviously that won't apply if you're using a device which can operate on the higher voltages but there aren't many of those).
For most types of electrical appliances normally used by travellers the different frequencies (60Hz and 50Hz) shouldn't make any great difference but a few devices might not operate properly.
For a list of the world's electrical supplies, with pictures of the types of plugs which are in use, see here:
http://www.kropla.com/electric2.htm
Chris