So you do not have to wait for an "announcement" or a thread here, you can find the NBC Primetime Schedule for shows 2 weeks early by clicking here: http://snurl.com/NBCPS, or the long url is here.

If there is a new HEROES episode (and I think I read that there will be 11 weeks straight of new eps until a rerun, so there are 5 more new ep descriptions in a row to come, from episode 7 to 11), then it will show up in the schedule that nbcumv releases. A new schedule comes out every Friday.

Also, tvguide puts out their episode details almost 2 weeks earlier, either on a Tuesday or Wednesday for HEROES, but I haven't ever paid enough attention to know which day.