As per CBDT circular no. 03/2011 dated May 13, 2011, TDS Certificates in Form No. 16A will be generated from Tax Information Network (TIN). It is mandatory for Companies and Banks to issue Form 16A from TIN to their deductees for deductions made from April 1, 2011 (F.Y. 2011-12 onwards). Circular attached for reference.

Deductors other than Company and Banks can also request Form 16A from TIN.
Form 16A is available for F.Y. 2010-11 also on the TIN website.
It is available to TANs registered at TIN website (www.tin-nsdl.com). Register your TAN online at the TIN website now for Form 16A from TIN.
Brief procedure for receiving Form 16A from TIN website:
1. Login to TAN Registration Account with user id, password and TAN.
2. Request Form 16A by carrying out verification by providing details of challan and deductees present in the TDS statement for which Form 16A is requested.
3. Form 16A will be provided on successful verification.
4. Two attempts within a day for successful verification are provided.
5. On successful verification, request number is generated and text file containing Form 16A details is e-mailed within 48 hours at the e-mail ID present in the registered TAN account.
6. In case of large number of records multiple files of Form 16A are created and will be sent through multiple emails.
7. Convert the text file to Form 16A by passing the text file through the PDF Convertor Utility. The utility is available to registered TAN post login.