I did a month at an HIV office (no peds), and my advice is to get a Stanford Guide for HIV (they make them specifically for HIV), and the JOhns Hopkins guidelines book (the newest one is brown, the previous one was blue). (I don't have them on me right now, sorry for the lack of specifics). HIV treatment changes so rapidly, that besides those 2 books, almost any books that are published will be out-of-date. The best way to learn is from the attendings. I couldn't believe the complexity to treating HIV. It was a great month. Good luck.