Oracle documentation is clear, comprehensive and FREE!... check here http://www.oracle.com/pls/db102/portal.all_books
If you have Transact-SQL skills please take into consideration things are not that straighforward in the Oracle side, SQL and PL/SQL are not the same.
You may want to start with PL/SQL
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Pablo (Paul) Berzukov
Author of Understanding Database Administration available at Amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.