I'm considering the purchase of a webcam and curious to know if it will work when I email friends in Europe (I'm in the U.S.)

im not sure what relevance emailing has to a webcam?
If youre referring to using a program such as skype... location wont matter.
Clarification on your question will help get you better answers :)

I have no problem emailing friends overseas. My question is this: If I buy a pair of webcams and send one to a friend in Italy, will we be able to use them to see each other when we're on line together? I have heard that there is a differnt electronic system in use in Europe and am concerned about compatability with U.S. hardware being used on the European system.

Webcams plug into USB ports and USB ports are universal in all computers (except for really old computers with USB 1 but there are fewer of them by the day).

Rik summed it up pretty well. As long as there's USB, you're golden. :)