FWIW
When I called iListen (in NH) yesterday (as instructed by the minions manning their booth at MacWorld) I was told to open my yet un-opened box of iListen (purchased in December), install it, get the "code number", therein, call back with that number and for an additional $29 I could receive the latest and greatest.
The only thing I'd be cautious with, Mayo, is to get advanced reassurance that "the deal" applies to iListen copies purchased now, rather than late 2007.