PostgreSQL For Beginners

One of the programmers I work with is interested in migrating from
Oracle to PostgreSQL as the backend for his applications.

Is there a PostgreSQL "beginners" guide available somewhere, which
might help him understand setting up a test database on his Windows
system?

I may also be performing a 30-60 minute presentation to several of the
developers as a "introduction" to PostgreSQL.  Any suggestions on what
I should cover in this presentation?

Topics I've considered so far are the following:

Designing databases with security in mind
Creating your first PostgreSQL Database
Understanding Roles and host-based authentication
Understanding permissions
Creating a table
Writing procedures


Please keep in mind my primary focus is database security, so if I've
left out something a beginner should know that is glaringly obvious,
be kind!
I'm going to try not to include information such as configuring WAL or
the error log, as I will be configuring these settings once PostgreSQL
is installed.

Thanks a lot!

Ken