howto have unique ID Number for each record

howto have unique ID Number for each record

Hi

i have made a database input form using creator application form to maintain record of the course participants that i conduct.

I want to give a Unique registration I.D. number to each applicant .

eg.
.
I.D. # NAME

001-2008 John Sane
002-2008 Amber sirf
003-2008 Extril nom

I want each to have a permanent ID number to track them.

can anyone tell me how to increment those ID. #? any code where to put how to do it.. Thanks in advance..Please help