getting number of rows updated within a procedure

I'm writing a procedure and I want to check the number of rows updated.
But I can't figure out how. I know UPDATE returns "UPDATE #" but I
don't know how to use that to get what I need.

Here's an example:

CREATE FUNCTION "test" () RETURNS int AS ' DECLARE
v_number_of_rows int;

BEGIN update bigtable set email_confirmed = 1
where user_group = 1234;

-- and here, I want to know the number of rows updated
v_number_of_rows := *what?*;

END; ' LANGUAGE 'plpgsql';

Thanks.

--
Dan Langille
The FreeBSD Diary - http://freebsddiary.org/
FreshPorts - http://freshports.org/
NZ Broadband - http://unixathome.org/broadband/