temp table creation

What's wrong with this function? The syntax is supposed to be right,
isn't it?

Create function UsaTablaTemporal()
RETURNS integer
AS '
BEGIN

SELECT p.apellidos, p.nombres, u.username
INTO TEMP TABLE mitabla
FROM persona p, usuario u
WHERE p.idpersona = u.idusuario
AND p.idpersona = 3278;

RETURN 1;

END;'
LANGUAGE 'plpgsql';

If I run:
select usatablatemporal();

I get the message:
ERROR: parser: parse error at or near "temp"

Thanx