You also have to note the voltage of your power supply. If it says in the label 100-240V, then you're in luck and all you need is an adapter to convert the 2 prong US to a 3prong UK plug. UK runs on 220V, so if you're power supply says only 110v, then you'll have to get a transformer too.

In the second scenario, better option would be to purchase an iGo power supply there 100v-240v and use that anywhere you go to.

 

Just about all laptops have a variable power supply (this means that it automatically adapts to the local current). As the previous poster stated, Europe is on 220v. So, just look on the power supply in the section marked "INPUT", it will probably say 100-240v and 50-60hz (Europe is on 50hz and US is on 60hz)

So, you just need an adapter for the plug, if it is for Madrid then it is a plug for "Western Europe", you can get buy this in the airport if you want.

For other electronics/electrical you have to look at the power supply as above. Most desktop computers have a little red switch on the power supply so you can change it from 110 to 220. But don't get it wrong, or you will fry your power supply. Usually you will plug it in, here a pop, and smell a sulfur smell emitting from your computer (don't ask me how I know this)

If it is only marked 110v/60hz then you may be able to use a transformer. These actually transform the electricity to 110v so your electronics can work but they are limited as to the wattage they support. Most electronics aren't a problem (computers, monitors, printers) but things like vacuum cleaners, coffee machines, irons, etc. need to much power for these transformers typically and you are better off buying French ones when you get here.

Also, the transformers do NOT transform the frequency, so it will make it 110v but 50hz, which generally isn't a problem. But digital clocks use the frequency to determine the time so they do not keep correct time in europe.

 

I use a Skype SMC WI-Fi phone and I had bought it in US. I carried it along when I shifted to london, cause its Wi-Fi and very easy to use. I just needed an adaptor, nothing more to use it.

[url = http://accessories.skype.com/item?SID=9 ... KP100PROMO] Skype [/url]

 

Just a word of caution - if you want to be able to watch European DVDs on your laptop... I had to change the zone settings on mine, and got a warning that I'd only be able to do that a total of 5 times.

So, I can't really switch casually between North American and European DVDs...pretty much have to pick a zone and stick with it!

 

I watch my DVDs with my PC. Using DVD region free software.
On this site you can find adapters:
http://www.dvdoverseas.com/voltage_converters.htm