Quest software has a series of videos called "Toad Tips and Tricks Video Series" that provide Tips that can also be used with SQL Navigator (so it could be used for a "SQL Navigator Tips and Tricks videos Series" :-) ).
Two of those features are the Quest SQL Tracker (called Oracle SQL Tracker in TOAD) and the Code Roadmap.
I really like Quest SQL Tracker because it allows to capture the SQL statements being executed from windows applications running against the Oracle database, see a list of the bind variables issued from those statements, associated times, etc..
Quest SQL Tracker video:
Code Roadmap video: