Here is a little cheat sheet for getting Postgres setup on Ubuntu and creating an initial database and database user.  This will work if you are wanting to use Postgres with Django.

Install postgres and the python libraries:

sudo apt-get install postgresql-8.4 postgresql-client-8.4 python-psycopg2

Modify the config file to allow local connections:

sudo nano /etc/postgresql/8.4/main/pg_hba.conf

Add the line:

local     all         all     md5

Save the changes to the file and restart the server.

sudo /etc/init.d/postgresql restart

Set the password for the postgres user:

sudo passwd postgres

Change to the postgres user:

su - postgres

Create a new Database:

createdb mydb

Login to the postgres shell and point to our new database:

psql mydb

Now from the postgress shell create a user and give him access to the database:

mydb=> CREATE USER myuser WITH PASSWORD 'myPassword';
mydb=> GRANT ALL PRIVILEGES ON DATABASE mydb TO myuser;
mydb=q

Done!