super beginner setting up postgresql for the first time

I am so glad there is a novice list, because as a brand new user, I have
plenty of naïve questions.

I am running Mac OSX 10.6.5 on a MacBook Pro. I am trying to learn to use
Postgresql for the very first time in order to use PostGIS and GeoDjango.
for now, I'm just trying to run it on my laptop while I learn the basics.

I recently installed postgresql82 with MacPorts but I can't login to psql,
postgres, or postmaster when I run them from terminal.
They request a password for my username, but will not accept any password
that I know or would have made myself.
I tried using the bash configuration commands listed
here<http://shifteleven.com/articles/2008/03/21/installing-postgresql-on-leopard-using-macports>,
but I still couldn't login.
I then tried to create a new user account with the name postgres but
received an error saying that a user already existed with that name, even
though no user by that name is listed anywhere.
I found a way to delete the account, even though it wasn't liste, and I made
a new account with the name "postgres" that is able to administer the
computer.

I still can't login, because it seems to have associated some password with
my username that I didn't make

I think I've made a mess, and I'm not sure where to fix things. I assume
that I need to learn more about configuring the initial setup. I have read
the online documentation, and done a lot of searching, but I'm still lost. I
assume that I need to have a user account set up in order to use the initdb
command.

So my questions are:
How should I create a user account/password for postgresql and create my
first database to get going? Should I just uninstall and start from scratch?
Is there a configuration file I can edit to reset my password and username?

Thanks and sorry for asking such a terrible question.

Looking forward to learning postgres,

-Ben