Refund of excess interest on tds challan paid

Though income tax department has provided for refund of taxes through Form 26B.  However it is required to be filed online and the online link has not yet been activated.

Alternatively, you can adjust it against your future TDS liability.

can form 26B be filled for FY 2011-12 also as mechanism of tds refund comes in the 2012-13 

Yes.  but the portal to  file Form 26B online is yet to be activated.  Thus, you wont be able to use it.

how can i add unconsumed challan for next quarter TDS return.