One of the highlights of Oracle Open World 2008 for me was the presentation by Bryn Llewellyn (PL/SQL Product Manager) on 'Doing SQL in PL/SQL: best and worst practices.'
Bryn surely has the most thorough and clear understanding of the PL/SQL language of anyone I have met (definitely including me).
His talk was detailed and precise (and maybe just a little bit overwhelming. He needed twice the time allotted) on this most important topic.
The bad news about this talk is that most PL/SQL developers will never be able to hear Bryn present it.
The good news is that everything he talks about (and more) may be found in a newly published whitepaper of the same name.
Simply visit the Oracle Technology Network PL/SQL Homepage and click on the hyperlink for that paper.
Notice also that Bryn has published an in-depth whitepaper on SQL injection, a very serious and widespread security risk in many applications.