<p>American students do not need to sit A-levels. If you check out the link Tarhunt posted you can see the requirements for US students...a brief outline from that link is copied below</p>
<p>Though there are no formal requirements, successful candidates would generally have an excellent High School record, supplemented by:</p>
<pre><code>* Scores of at least 700 in Verbal, 700 in Math and 700 in the Writing Test in SAT I (or 2100+ combined)(Or ACT with a score of at least 32 out of 36)
</code></pre>
<p>We would also expect:</p>
<pre><code>* SAT II in a good spread of three or four subjects at 700 or better;
* Or, preferably, grades 4 or 5 in two or more Advanced Placement tests in appropriate subjects
* Alternatively, a mixture of SAT II and Advanced Placement scores; both should be at the levels indicated above.
</code></pre>
<p>We also welcome candidates sitting the International Baccalaureate; successful</p>