Real novice question: Roles

Hi.

I've just installed PostgreSQL 9.0.5 server & I can get the server running
by doing:

=========================================================================

$ sudo su
Password

sh-3.2# su postgres
bash-3.2$ whoami
_postgres

bash-3.2$ /opt/local/lib/postgresql90/bin/postgres -D\
> /opt/local/var/db/postgresql90/defaultdb
LOG: database system was shut down at 2011-11-18 03:19:30 GMT
LOG: autovacuum launcher started
LOG: database system is ready to accept connections

=========================================================================

`psql --help` tells me that I'm the default user (I'm the administrator of
the machine) but after Googling for hours I can't create a role or create a
database. I've followed the instructions in the PostgreSQL manual for this
version of pgsql to the letter but no go.

Any help appreciated.

Cheers,

Phil.

--
Nothing to see here... move along, move along