How to retrieve the serial number of an INSERT?

I have the following scenario, and I'm sure many others have wished to do
something similar. I perform an insert into a table where one field is a
SERIAL. I wish to perform several other inserts (on other tables) that will
reference the first record based on its SERIAL field. In the application, I
wish to name a file based on the SERIAL (I don't wish for postgres to name
the file for me, I would just like to get at the number).

The specific table is listed below. To recap, I wish to perform an insert
and also receive the 'id' field value back. Is there any way for me to do
this, or is there a better technique for achieving what I wish to do?
Thanks!

Daniel

CREATE TABLE photos (
    id serial NOT NULL,
    parent_id integer NOT NULL,
    photographer_id integer NOT NULL,
    title character varying,
    description character varying
);