In addition to the O'Reilly books listed in the previous section, there are other printed resources you should be aware of:
Oracle documentation
Oracle has come a long, long way from its early days of scattered and inadequate product documentation. The HTML documents that come with the RDBMS are an excellent source of information on the incredible array of technologies now offered by Oracle.
Oracle Press and other publishers
Oracle Press offers its own PL/SQL series by Scott Urman. Other technical publishers offer introductory texts for PL/SQL or include coverage of PL/SQL within broader Oracle-related books.
Oracle Professional from Pinnacle Publishing
This monthly, printed newsletter (with accompanying online edition) offers in-depth articles on Oracle technology. Each issue features a PL/SQL article (usually written by Steven Feuerstein) that explores either new features or applications of PL/SQL technology.
http://www.oracleprofessionalnewsletter.com/
Oracle Magazine from Oracle Corporation
A monthly publication that covers a wide variety of Oracle technology, Oracle Magazine often introduces new PL/SQL functionality and gives you a solid foundation for understanding how all the Oracle pieces fit together.
http://www.oramag.com/
1.5.3 PL/SQL on the Internet
There are also some excellent web sites available to PL/SQL programmers:
Oracle Technology Network
Join the Oracle Technology Network (OTN), sometimes called TechNet, which "provides services and resources that developers need to build, test, and deploy applications" based on Oracle technology. Boasting membership in the millions, OTN is a great place to download Oracle software, documentation, and lots of sample code. Check out:
http://technet.us.oracle.com/
or the PL/SQL page more specifically:
http://otn.oracle.com/tech/pl_sql/content.html
PL/SQL Pipeline
We also recommend that you join the PL/SQL Pipeline, described as "a free Internet portal community hosted by Quest Software. This site is designed to inform, educate, and inspire IT professionals around the world. The Pipeline is regularly monitored by a host of industry-recognized authors and experts." The PL/SQL Pipeline offers archives of training materials and useful code. The Pipetalk forum features many active discussions and, in essence, free consulting for developers and DBAs around the world.
http://www.quest-pipelines.com
PL/Net.org
PLNet.org is a repository of open source software, maintained by Bill Pribyl, that is written in PL/SQL or is otherwise for the benefit of PL/SQL developers. You can read more about the project's background or check out the FAQ (Frequently Asked Questions). You will also be directed to a number of utilities, such as utPLSQL, the unit-testing framework for PL/SQL developers.
http://plnet.org
Open Directory Project
Courtesy of the "dmoz" (Directory Mozilla) project, you can find a choice set of links to PL/SQL sites. There is also a subcategory called "Tools" with a fairly comprehensive set of links to both commercial and noncommercial developer tools. Links on these pages are maintained by a team of volunteer editors, currently including Bill Pribyl.
http://dmoz.org/Computers/Programming/Languages/PL-SQL/
Oracle FAQ
This site offers "independent and useful information on Oracle products to the Oracle community. On this site you will find FAQs, Scripts, Tips, News, Jobs, Directories, Message forums, Chat boards, and many more features to make your journey with Oracle more worthwhile."
http://www.orafaq.com/faq.htm