I changed my postgresql.conf to have:
log_statement = mod
It appears to be working, though not logging *all* INSERTs. For 
instance, I have a PHP class that inserts into two tables in a 
transaction. The log shows the first, but not the second. Has anyone 
seen this behaviour?
test=# show log_statement;
  log_statement
---------------
  mod
(1 row)
brian