... However, I think there's still value in schedules. Without schedules things just don't get done, in my experience.
Or at least deadlines. Note that this ties in with frequent releases: if we said we won't release something "until it's ready", and the time between releases slobbers out to over a year again, then people will fight like hell to get "just one more" change in -- over and over and over again. Almost nothing is ever really finished. Frequent releases make it much easier to sell "too bad, you're too late for this release, but you'll get another chance in 6 months".