Log file Query

hi ppl,
I am using postgres7.3 version. I am unable to find any log.
all the files
1) /usr/local/pgsql/data/serverlog
2) /var/log/pgsql
etc are empty
pg_xlog and pg_clog directory files dont seem to be meaningful.

i tried
log_connections = true
log_pid = true
log_statement = true
log_duration = true
log_timestamp = true
log_min_error_statement = debug5

but where this log_statement log will go...

Moreover where databaseserver log is made
i m starting postgres as:
service postgresql start

i mean when database server is improperly shutdown or some other error condition etc must be logged somewhere
is it in the serverlog file.??
Moreover i want to log all the steps that postmaster makes at startup...

can anyone help me on this