DBA Interview Questions - check out

You can check out http://www.geocities.com/oracle_interviewquestion/ for lots of interview questions.There are 95 pages having about 10 questions in each page.

Another site to check out is: http://www.newinterviewquestions.com/

It has a few questions on each topic, the links are left intact if you wish to check out each section.

Oracle Apps Interview Questions
AOL Interview Questions
AR Interview Questions
D2K Interview Questions
Flexfields Interview Questions
GL Interview Questions
ONT Interview Questions
Oracle Apps Basics Interview Questions
Oracle Apps Security Interview Questions
Oracle Apps Technical Interview Questions
Oracle Forms Interview Questions
Scope and Application Interview Questions

Oracle Interview Questions
Backup and Recovery Interview Questions
Concepts and Architecture Interview Questions
Data Access Interview Questions
Database Administration Interview Questions
Database Security Interview Questions
Distributed Processing Interview Questions
General Oracle Interview Questions
Memory Management Interview Questions
ONT Interview Questions
Oracle Architecture Interview Questions
Oracle Backup and Recovery Interview Questions
Oracle Forms 3.0 Interview Questions
Oracle Forms 4.0 Interview Questions
PL-SQL Interview Questions
Programmatic Constructs Interview Questions
Scenarios Interview Questions
SQL In Oracle Interview Questions
SQL Plus Interview Questions

DBA Questions on RAC, performance tuning

http://neworacledba.blogspot.com/2008/04/performance-tuning.html

This site has RAC tutorials, resources, download links.
Has questions pretaining to performance tuning, RAC, ASM, VM, ...

Oracle DBA tutorial

http://www.hot-oracle.com/
This site has Oracle DBA tutorials, also SQL Plus, PL/SQL tutorials.
Has a discussion forum for all Oracle related topics, installation, troubleshooting ...

Free practise questions for Oracle

http://www.qod.us/index.php?action=sq

Free practise questions for Oracle and MCSE,Solaris, Redhat, CISCO exams and a lot more.

Premium membership available

http://dba.fyicenter.com/faq/oracle/

This site has lots of questions for Oracle

Forums

http://www.lazydba.com/ - Oracle,SQL,DB2 forums and archive

Books

http://free-oracle-ebooks.blogspot.com/