Oracle Beginnings - Where to Start?

Scalli0n asks: "I'm a programmer with a solid computer science background, but I'd like to know where I should start with the behemoth that is Oracle - my bosses tell me that I need to learn it to store geodatabases (since I work with geospatial intelligence) and I have no clue where to start since nobody can even tell me of a good beginners book - any suggestions?"