There's a small book kiosk inside the main entrance to the Auschwitz museum where you can buy booklets and maps to self-guide your way through the camps. Otherwise, there's not much on-site provision for visitors. It's best to stock up on info at one of Kraków's tourist information centers. The Austeria bookstore (Józefa 38; tel. 12/430-68-89) in Kazimierz, next to the High Synagogue, is an excellent source of information and books on Auschwitz and the Holocaust.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.