Income tax return

Can Income tax Return for the A.Y 2010-11(FY 09-10) be filed now till 31st march 2012 ?

 In my view it can be filed but penalty would be applicable u/s 271F for Rs. 5000/-. My question is whether penalty should be paid before filing the return on 31st march or only it should be shown in return and would be paid later on when notice will be isued for that or at the time of assessment. when penalty will be paid?