DECLARE
  commit_number := 0;
BEGIN
  INSERT INTO abc (xxx) values (yyy);
  commit_number:= commit_number+ 1;
  IF MOD(commit_number, 5000) = 0 Then
   commit;
  END IF;
END;

DECLARE
 CURSOR TEST IS
  SELECT COLUMN_1 FROM ABC;
 COMMIT_NUMBER NUMBER := 0; 
BEGIN
 FOR CUR_REC IN TEST LOOP
  INSERT INTO XYZ (COLUMN1) VALUES (CUR_REC.COLUMN_1);
  COMMIT_NUMBER:=COMMIT_NUMBER+1;
  IF MOD(COMMIT_NUMBER, 5000) = 0 THEN
    COMMIT;
  END IF;
 END LOOP;
END;

SQL> create table t as select * from dba_objects where 1=0;

Table created.

SQL> set timing on
SQL> insert /*+ APPEND */ into t select a.* from dba_objects a, dba_objects b where rownum <=2500000;

2500000 rows created.

Elapsed: 00:01:06.10

OS: Windows XP Pro (Version 5.01.2600)
   Service Pack 2 (2.0)

Processor: Intel Pentium M (0.09�)
   (Intel(R) Pentium(R) M processor 1.86GHz)
   1 Processor(s) 1861MHz
   Cache: L1code=32K L1data=32K L2=2048K 

Memory (Available Ko) :
   Physical: 256.112 / 1.047.960 (24%)
   Paging: 1.618.492 / 2.519.400 (64%)