After submitting my resume/cover letter, they asked that I take an online aptitude test. The test had a number of analytical questions - it was rather similar to the LSAT ("If A, B, C, D, and E have appointments on Monday, Tuesday, Wednesday...") except that it had some questions asking to follow and describe flowcharts, and some other pretty dumb questions about counting the number of times a certain letter appeared in a paragraph. The questions were timed.
I must've done alright (the LSAT prep I'd done separately proved rather helpful) since they asked me to come to New York to interview and tour their headquarters.