use syntax like this.
to_date('2011/04/22 08:30:00', 'yyyy/mm/dd hh24:mi:ss')
for you its like
Insert into PEPSIRENDEEMHISTORY(PIN,STATUS,CURRENTDATE,MSISDN,USERNAME,SIM)
VALUES ('4501664170',1,to_date('2011/04/22 08:30:00', 'yyyy/mm/dd hh24:mi:ss'),'2348121846632','ranjith-PC\ranjith',1)
-SG