sudo apt-get install postgresql
sudo apt-get install phppgadmin
sudo apt-get install pgadmin3

After installation the postgres password of postgresql can be changed like this :

ALTER USER postgres WITH ENCRYPTED PASSWORD ‘<***password***>‘;

To exit :
\q

Also create a database :
sudo -u postgres createdb mydb

Now to access localhost/phppgadmin a link needs to be created which points to /usr/share/phppgadmin :

?ln -s /usr/share/phppgadmin /var/www/phppgadmin

Now localhost/phppgadmin should open up

Trying to login with user : postgres and password : created above might give the error :
Login disallowed for security reasons.

To fix this edit /usr/share/phppgadmin/conf/config.inc.php
and change :
$conf['extra_login_security'] = true;
to
$conf['extra_login_security'] = false;

and then login again from phppgadmin and it should work fine.

Alternatively pgadmin3 can also be used to work with postgresql.
Start pgadmin and create a new connection using the icon on top left and it should work fine.

References :
1. Ubuntu Help