PostgreSQL dirver?

I have taken the task of installing and investigating PostgreSQL.

Using Debian's 'apt-get', I have installed PostgreSQL, this had
the advantage of a brainless and quick installation. I was able to
create a database in literally seconds after creating my account.
However, it has a drawback; I have no idea where the application
was installed nor where any of the help files are, for that I have
to do a more in depth research of the Debian's file system. But if
anyone here can give some hints it will be very, and I mean VERY
MUCH appreciated.
For the time being though, I am installing "Qt-3.0.0". To do this
I need to specify what sql driver I want to use to hook
up future applications to the PostgreSQL database. So, my question
is: what would be the driver, if any, that I have to specify in the
'./configure' '-qt-sql-<driver>' parameter?

Thanks in advancer