Different countries have different types of power plugs and different mains voltages and current frequencies. You can find information about power across the world in several places on the Web:

 * [Power plugs](http://en.wikipedia.org/wiki/Power_plugs) and [Mains electricity by country](http://en.wikipedia.org/wiki/Mains_electricity_by_country) in Wikipedia, and the map of [voltage and frequency](http://en.wikipedia.org/wiki/File:Weltkarte_der_Netzspannungen_und_Netzfrequenzen.svg) and the map of [plug types](http://en.wikipedia.org/wiki/File:Weltkarte_verwendeter_Netzsteckertypen.svg) by country.
 * [Electrical outlets by country](http://electricaloutlet.org/)
 * [International power, plugs and language](http://www.dbicorporation.com/internat/intpower.htm)