International Schools for US Students

<p>As a freshmen in high school, I have been doing a fair amount of college research but I haven't been able to find much information about US students applying to, or attending, schools in Europe or Canada. So I was just curious about American high students attending schools outside of the states:
-How does the university experience differ?
-Are admissions more or less difficult than equivalent US schools? (and what requirements do European schools have for international student admissions)<br>
-Do US students tend to go to these schools for graduate school rather than undergraduate?
-Advantages? Disadvantages?
-What are the prestigious European schools? (I know of, of course, Oxford and Cambidge, plus I've heard good things about St. Andrews, any others?)
Thanks!</p>