I occasionally am asked about naming conventions for PL/SQL program units.
I did publish a document back in 2009 (link below), but there are also other sources for naming conventions from others, offering different ideas and excellent motivation for standardizing the way you write your code. I have collected links to them here.
The most important thing about naming conventions is BE CONSISTENT.
PL/SQL Naming Conventions and Coding Standards - Steven Feuerstein 2009
Coding Standards for SQL and PL/SQL - William Robertson
ORACLE-BASE / Tim Hall / Oracle Naming Conventions
Trivadis PL/SQL and SQL
Coding Guidelines Version 2.0
Ask Tom on Naming Conventions
PL/SQL and SQL naming conventions
Oracle SQL and PL/SQL Coding Standards – Cat Herding for Dummies
Slideshare Presentation on PL/SQL Coding Conventions