18 June 2009
Dear Radha The above new system will be effective for all tax deducted at source or tax collected at source on or after the 1st April, 2009. However, any TDS or TCS effected on or after the 1st April, 2009 but not later than 31st May, 2009 shall continue to be paid to the credit of the Central Government by using the old challan form. The TDS or TCS effected on or after the 1st June, 2009 shall be required to be paid electronically by electronically furnishing income tax challan in Form No. 17
18 June 2009
The CBDT has decided to defer the implementation of Notification No.31/2009 dated 25.3.2009 amending or substituting Rules 30, 31, 31A and 31AA of the Income Tax Rules, 1962. The amended / substituted Rules will now come into effect on 1st July 2009 instead of 1st April 2009.
Therefore,the answer to your query is 1st July 2009.