Postgres superuser & password on Red Hat; upgrade?

Hello all,

I get the feeling that this is an EXTREMELY novice question. I am very
new (within a few weeks) to both Linux and PostgreSQL. I did my best to
RTFM, but I finally had to break down and mail the list. I apologize if
this is a really obvious one.

When we decided to use PostgreSQL, we got a completely new box. Red Hat
6.2 was installed. During the installation a GUI offers a checkbox for
installation of PostgreSQL (via RPMs). This installs PostgreSQL 6.5.3.

So far, most things seem okay. But I am unable to figure out what the
deal is with the Postgres superuser, which is automatically installed by
Red Hat. I have seen no mention of a default password, but Postgres does
seem to have a password. I tried to use Linuxconf or Userconf as root to
give Postgres a new password (as I have seen from looking through lists
that others have done), but it freezes up after I type the new password
for the second time and hit enter. This crash happens consistently at
the same point.

The only way I can become Postgres is to log in as myself (Laurel),
become substitute user--root by typing "su" and entering the root
password, then typing su - postgres--thus bypassing the postgres
password. But that makes Postgres also root, which I understand to be
very bad thing. I have used this technique to make Laurel a database
user, but how can I make Postgres a DBA login with full privileges who
is NOT root? What is the method to give Postgres a new password and/or
discover the old one? Or should I just use Postgres-as-root to give a
different Linux user PostgreSQL superuser privs and forget about
Postgres after that?!

It may be that an inadequate understanding of Linux is contributing a
lot to my problems!

I have a second question as well. I see most of you are running 7.0.3.
Should I upgrade at once, and if so, are there any quirks deriving from
this Red Hat installation process that I should know about?

Many thanks in advance for your help.

Laurel Williams