Unable to start postgresql server 8.3.1.1

[Vittorio]

having always used postgreSQL satisfactorily under FreeBSD I installed  
postgresql83 & postgresql83-server on my leopard Macbook via

sudo port install postgresql83 postgresql83-server.

The process concluded successfully . I ran as requested:

sudo launchctl load -w /Library/LaunchDaemons/ 
org.macports.postgresql83-server.plist
  sudo mkdir -p /opt/local/var/db/postgresql83/defaultdb
  sudo chown postgres:postgres /opt/local/var/db/postgresql83/defaultdb
  sudo su postgres -c '/opt/local/lib/postgresql83/bin/initdb -D /opt/ 
local/var/db/postgresql83/defaultdb'

BUT
sudo launchctl load -w /Library/LaunchDaemons/ 
org.macports.postgresql83-server.plist  gives the following

victor$ ps ax|grep postgres
   383   ??  Ss     0:00.00 /opt/local/bin/daemondo -- 
label=postgresql83-server --start-cmd /opt/local/etc/LaunchDaemons/ 
org.macports.postgresql83-server/postgresql83-server.wrapper start ; -- 
stop-cmd /opt/local/etc/LaunchDaemons/org.macports.postgresql83-server/ 
postgresql83-server.wrapper stop ; --restart-cmd /opt/local/etc/ 
LaunchDaemons/org.macports.postgresql83-server/postgresql83- 
server.wrapper restart ; --pid=none


and I don't see any process with the usual "postgres" name when I run  
top.

Could you help me straightening postgresql up?

Ciao
Vittorio