A couple of general guidelines for foreign power requirements. The USA runs at 120Volts/60hz (hertz or cycles). The rest of the world is generally at 240Volts/50 hz.
When you travel you have to solve two things, 1) the physical plug. Getting the device adapted into the right plug to go into the wall and 2) matching the power needs of the device you are plugging in to whats coming out of the wall.
Never, ever plug in a device like a hair dryer, curling iron, etc into a wall socket if the voltage and hertz don't match the device, EVEN if you can get it to physically plug in! You'll fry it if you try!
Now there are some devices like laptop power supplies, some cell phone adapters, ipod adapters, etc that will handle both 120 and 240. To check look on the power adapter on your device, it will say right on it if it can support both 120v/60hz and 240v/50hz. If it does, then all you need to do is get the adapter and plug it in.
If your device does NOT support 240V/50hz then you need an adapter AND a transformer. The transformer changes the voltage and hertz to match the USA standard. A slight complication here though is you need to know how many watts your device uses. Some high powered devices (200-1500 watts) need a special transformer. Low power device (less than 50 watts) can use a small transformer thats often included in the universal adapter kit. Some transformers can handle both Hi and Low with a switch on it.
Helpful link:
To see a list of all the country plugs and sockets, find out where you are travelling and then check here:
http://www.kropla.com/electric2.htm
Most places will sell these 'universal' adapters that support the plug adapters for almost all countries.
Note the for dial up telephone you have the same issue, many different types of adapters. Most people are using wireless these days but if you needed to use computer dial up to a laptop you will need a phone plug adapter. You can find those here:
http://www.kropla.com/phones2.htm
Hope that helps!
