Log SQL code before executing it

Dear PgSQL users,

is there please a way to display the executed SQL code?

I'm using phpBB 3.0.4 / PostgreSQL 8.2.6 / PHP 5.2.5 / OpenBSD 4.3
to develop a card game in Flash / C / Perl (at http://preferans.de )
and would like to log each game round by simply posting and replying
in one of the phpBB forums. The phpBB's code however is very hairy
and I have troubles to follow it and to reconstruct the SQL statements
needed for posting and replying.

Thank you for any hints
Alex

PS: Or maybe it's possible to overload $db->sql_query($sql) in PHP?