yes, the voucher are available through SAI registration but this is for students and new registration close by ORACLE .Students get 40% discount through it but you can't register in it. But you can search the student nearby you who registred in it before 27th JAN 2010(before ORACLE acquires SUN) and contact to get discount voucher and may be this offer closes on 31 DEC 2010 i am not sure. If you want know further knowledge about it then visit the SAI page
http://osum.sun.com/group/saiusersgroupAND there is more option, like you can directly contact vicinity NIIT and PROMETRIC center they also sell voucher at discount price.
Regards
vinit