30 September 2011
The liability to pay advance tax will be once you have crossed the tax liability of Rs. 10000/-. Interest u/s 234B will be calculated @ 1 % from April 1 of the relevant assessment till the date of filing the return, and 234C interest will be calculated @ 1 % based on the percentage of advance tax which should have been paid as per the provisions.
Here one notable point is that TDS should not be deducted from the total tax liability for payment of advance tax.