Pardon my ignorance, I guess I don't follow you, really, but here I get:
andrei:~> date
Sat Aug 31 15:46:09 CEST 2002
and
andrei=# select substr(now() at time zone interval '-05:00',1,19);
substr
---------------------
2002-08-31 08:46:12
(1 row)
Is that's what you're looking for? This is on FreeBSD 4.6-STABLE with PostgreSQL 7.2.3.