SQL & PL/SQL :: UNION ALL Output In Multiple Columns?

Following is my table structure:

14:54:17 PYMTPRODIAT@UCS43 > select * from DGTEST;

ID AMOUNT DI
---------- ---------- --
1 50 D
2 50 D
3 20 D
4 60 C
2 60 C
3 20 C

now, I want the output in the following format.what could be the easiest way.. I need the output in one query,,

ID D_Net_Amount C_Net_Amount
--- ------------- --------------
1 50
2 50 60
3 20 20
4 60