Making a function call from within a transaction block.

I am attempting to make this test work.. I have three tables

CREATE TABLE test1 (
my_id int
);

CREATE TABLE test2 (
my_id int
);

CREATE TABLE test3 (
my_id int
);

And the function

CREATE FUNCTION addTest2Value( int ) RETURNS integer AS '
DECLARE
value ALIAS FOR $1;
BEGIN
INSERT INTO test2 VALUES( value );

RETURN 1;
END;
' LANGUAGE 'plpgsql';

What I am attempting to do is this

BEGIN;

INSERT INTO test1 VALUES ( 1 );

addTest2Value( 2 );

INSERT INTO test3 VALUES ( 3 );

COMMIT;

However I get a syntax error at the addTest2Value.

If I use SELECT addTest2Value( 2 ); from what I've read in the docs I believe
that that will cause this routine to stop at the select and return to the
libpq-fe C interface...

I've also tried PERFORM addTest2Value but that is apparently only available
within a plpgsql function...

Any hints?

Thanks, Josh.