I am starting my second year/final year of my BSN. I don't know that there's necessarily a book that will help you prepare. I would recommend getting a good hard copy or electronic planner to keep you assignments, etc organized. Also brush up on your math for Pharm. There's lots of conversions to remember grams, microgram, milligrams, oz, millileters, liters, etc. Practice converting between them.
The most important thing is to spend as much time as you can with friends and family having fun. You wont have time once school starts.
Remeber it will be rough but you can do it.