How to get a result in one row

Hi!

I'm using PostgreSQL 7.4.7.

table_cid | nick   
----+------ 1 | T       2 | S      3 | G       4 | A       5 | D      
...

table_m  id |  c
------+----
22192 |  4
15041 |  3
21764 |  5
22192 |  1
15041 |  4
15041 |  2
...
where table_m.c is a foreign key on table_c.id

SELECT table_m.id,table_c.nickFROM table_m AS m JOIN table_c AS c ON c.id=m.c WHERE m.id=22192 ORDER BY c.nick;

returns:  id | nick   
------+------
22192 | A      
22192 | T      
(2 rows)

I'd like to get the result in only one row:  id | nick
------+------
22192 | A,T

(and similarly: 15041 | A,G,S )

As table_c can increase, I don't want to use the case construct.
How can I do? Maybe writing a function. But how?

TIA!
virgi