Links:
Oracle Technology Network - http://www.oracle.com/technology/index.html
Oracle Knowledge Base - http://oracle.ittoolbox.com/
Oracle Blogs - http://blogs.oracle.com/
Oracle Academy - https://academy.oracle.com/
Oracle Tools - http://www.orafaq.com/tools/
Oracle Development Tools - http://www.orafaq.com/tools/#Developer_Tools
Mastering Oracle Sql Book - http://books.google.com/books?hl=en&id=Rl2_4LhDjZkC&dq=oracle&printsec=frontcover&source=web&ots=gaYnrtP4J6&sig=0B8OKUXnQuHTJQ9bFFeNQSyODlA&sa=X&oi=book_result&resnum=6&ct=result
PL/SQL Best Practices: Optimizing Oracle Code Book - http://books.google.com/books?hl=en&id=BZ3xICLiwwkC&dq=oracle&printsec=frontcover&source=web&ots=Jr6svNlvdn&sig=83VgoXnDtddPh7p9zV359C9Eyr8&sa=X&oi=book_result&resnum=9&ct=result
Free and Open Source Software - http://oss.oracle.com/
Toad vs Sql Developer - http://oracle.ittoolbox.com/documents/popular-q-and-a/toad-vs-sql-developer-4625