debugging query to put message in pg logfile?

[postgresql-7.4RC2, python-2.3.3, PyGreSQL-3.4, SuSE x86 Linux 8.2]

I've started putting debugging queries like:
  select "opwin.py: committing step signoff"

in my app, just to have an entry in the postgres logfile.  These are
especially helpful in tracking down what piece of code did a 'commit',
since there's nothing to distinguish one from another in the log. 

Is there some cheaper (or more appropriate) sql statement that will show
up in the postgres log?  I thought I remembered a "message" sql statement
or something like that.

-- George Young

-- 
"Are the gods not just?"  "Oh no, child.
What would become of us if they were?" (CSL)