sequence values question

Hi, how can i know the values generated by a column of type serial?
I mean, i have the following table

productos
(
id serial,
desc varchar(50)
)

select * from productos;

+-----+------------+
| id | desc |
+-----+------------+
| 1 | ecard1 |
| 2 | ecard2 |
| 3 | ecard3 |
| 4 | ecard4 |
| 5 | ecard5 |
+-----+------------+

I insert a row using a SP, i want to return the id and desc of the new
product in the table.
this is an example of the hypothetical SP

CREATE OR REPLACE FUNCTION insert_row(text) returns text language plpgsql
AS $$
DECLARE
vdesc alias for $1;
BEGIN
INSERT INTO productos (desc) VALUES (vdesc);
RETURN (new id ???) || ',' || vdesc;
END;
$$
LANGUAGE 'plpgsql' VOLATILE;

I know i can get the last value using currval(text), and add 1 to the next
values, is this the only way?, what if i want to insert several products?,
should i return a record ?
thanks