You're right that the broadcast schedule is usually the first place these dates are officially publicized. It's a good idea to find those dates there; in fact, it's such a good idea that this option was already mentioned earlier in this threaddmaynes wrote:You might try asking the Stake Presidency. The church usually sends out a broadcast schedule well in advance for broadcasts coming over the satellite system. The General Conference broadcasts are listed on that schedule and will probably be one of the first official documents showing the date. It could very well be the case that some of these items have not been calendared yet.

When the 2010 schedule comes out, it will include all of those dates (subject to change, of course -- the 2009 Pioneer Day broadcast was just rescheduled barely a month before the event). But there's no point in asking the stake presidency for the schedule at this point, because the 2010 schedule has not been published yet.