Just as there are different languages and customs around the world, electricity voltages also differ. Along with this difference are the myriad of alternative accessories to access local electricity. It is important to know of these differences not only when travelling, but if you are wanting to export your product overseas and your product requires electricity, you need to know how to adapt it for the local export market conditions. Below are some links to useful information.

Electrical power around the world
Different plug types
General advice
Electricity travel guide