Reg: Nested query

Can anyone please help in getting a solution...
I have two table, 1 contains all details of a person with person id as
primary key.
the other table has person id and parent id both referring to person table
person id.
My query is i have to get all the parents of a given person name.
Please help me in finding a query solution...

Table "person"
Column | Type |
Modifiers
------------+-----------------------+----------------------------------------------------
pid | bigint | not null default
nextval('"person_pid_seq"'::text)
first_name | character varying(50) |
surname | character varying(50) |
dob | date |
Primary key: person_pkey

Table "parent_of"
Column | Type | Modifiers
-----------+---------+-----------
person_id | integer |
parent_id | integer |

so if i give first_name of person = ????, then i have get all the parent
ids. I tried nested query but tat resulted in 1 level parent alone.
i want to get all parent id... please help me..!

Reagrds,
Vignesh
--
"A man who believes in himself and not circumstances is the real winner"