The standard power supply that comes with the US 360 cannot be plugged into the wall. (I was unable to find a microsoft EU power supply).

As mentioned above by lob, the easiest thing to do is to buy a "step-down transformer", which plugs into the wall in switzerland, and converts the electricity into the correct US voltage (110v). Then you plug the xbox into this transformer instead of directly into the wall. btw, the small travel adapters dont work because they cant handle enough power on a continuous basis.

My transformer looks like this:
http://www.world-import.com/images/TC100-200B.jpg

The 360 will need a model that can handle at least 200 watts (I got a 500w step up & step down model).

For a tv, if you're bringing your US tv, then no worries. if you buy one here, just make sure it has inputs that match your 360 cable (I use the HD component cables with a samsung lcd i bought here, and it looks great). if the tv is a HD monitor (ie most flat panel tvs and other newer tvs) you can use the component or hdmi cables and not worry about the ntsc/pal stuff!

Only other thing to watch is that when you buy games here, you find a store that sells the US version of the game.