16 April 2010
But sir as per Notification No. 9/2010/F.No. 142/27/2009-SO(TPL), dated 17-2-2010 the form 16 & 16A notified are the old ones only i think.
You can download the notification from http://law.incometaxindia.gov.in/DitTaxmann/Notifications/IncomeTaxAct/2010/TDS_Notification.doc where the form 16 & 16A shown are the old ones only and the new one as there is the link have not come into effect i think.