If you do not want to use the version of PostgreSQL bundled with Ubuntu, the latest PostgreSQL binary files and source are available at www.postgresql.org. The PostgreSQL packages are distributed as several files. At a minimum, you want the
postgresql package. You should see the README file in the FTP directory ftp://ftp.postgresql.org/pub/ to determine whether you need any other packages.
If you are installing from the Ubuntu package files, a necessary
postgres user account (that is, an account with the name of the user running the server on your system) is created for you automatically:
matthew@seymour:~$ fgrep postgres /etc/passwdpostgres:x:26:26:PostgreSQL Server:/var/lib/postgresql:/bin/bash ...