Calypso, I am a new grad and just interviewed at two hospitals in oncology for an entry level position. I had done my practicum on an oncology ward during my last semester in school, and so had some basic familiarity with what an oncology nurse does. One hospital asked me about my experience with lots of oncological procedures and concepts (central line changes, IV starts, chemotherapy protocols), and the other place only asked me why I wanted to be in oncology. Weirdly, the second place was actually looking for an experienced oncology nurse and hired me instead, so you'd think they would have been more interested in my practical experience.
I read up on my oncology text before I interviewed, but I needn't have. If you don't have any student oncology experience it will be obvious from your resume, and if you do, it will far outweight whatever you can read from the book. I think the thing to do is just be ready to answer "why oncology?" There are so many new grads looking for jobs, that being passionate about what you want to do is one of the few ways you can distinguish yourself from the others.