This is the $64 billon question. The cards say that they expire. However, this could be just a "legality" that needed to be on the cards.
It would be really great if VMK would post something on the homepage or in the newsletter letting us know though - so we dont have to lock our little virtual selves in a room and frantically try to finish entering any codes we may have.
At this point, it is a coin toss as to what will happen on October 1st to those codes. (Anyone feel like at VMK Y2K?)