help with dynamic table name

Hi, could someone please let me know what i'm doing wrong here?

CREATE OR REPLACE FUNCTION sc_insert_row(char(32),text,varchar(32)) RETURNS
text AS $$

DECLARE sql text;
BEGIN
sql := "INSERT INTO "+ $3 +" ('id','body') VALUES ("+ $1 +","+ $2 +")";
EXECUTE sql;
RETURN '';
END;

$$ LANGUAGE 'plpgsql' VOLATILE;

I get the error: "ERROR: 42703: column \"INSERT INTO \" does not exist"

Cheers
Pete