Reset Database Field

I am currently auto generating project IDs with a format of 11-A-0000. 11 will be the year, A relates to a company (will also have B,C,etc.), 0000 is a sequential number. When it turns 2012, I want the sequential number to be reset to zero. Currently I am using the users system time to run a check on the year so it will reset the sequential number. I don't think this is the best way to go about this because if for some reason a users computer clock were to get changed, not sure why it would but stuff happens, it would screw up the ID creation process. Anyone have any other recommendations on how to check when a new year arrives and reset a DB field?