http://www.oracle.com/education/certification/

Oracle education site

http://dbasupport.com/

DBA Support

http://www.examnotes.net/oracle/

Exam notes on oracle

http://www.db.cs.ucdavis.edu/teaching/sqltutorial/

oracle tutorials

http://www.oracle-users.com/links.htm

links to oracle user groups

http://www.orafaq.com/index.htm

Faqs on oracle

http://www.oracleassist.com/

tutorials links

http://www.fors.com/orasupp/

Oracle Troubleshooting