In more detail, he did the following:
He created a free wiki using PBworks.
For each course, he created a page on the wiki for the next exam.
After each lecture, he put aside time to add the relevant notes to his wiki. To do so, he would create a subpage for each topic, and then list the main points, add snippets of sample code, or summarize any other information relevant for the exam.
Following the stealth studying philosophy, he would then access his wiki using his iPhone while walking to class and waiting for the lecture to begin, doing quick bursts of review. (PBworks plays nicely with iPhones, making it easy to browse the wiki on the run.)