Geocaching has the capability for you to hide a cache and publish it so that it remains hidden from view until a date in the future. This is handy for caches you wish to have published on the day of an event or an activity like the Moving Cache Races.
All future publications happen at 00:01 Australian Eastern Standard or Australian Eastern Daylight Time on the hidden date you have set for your cache listing. If you are in a time zone other that AEST or AEDT your cache may be published at a date and time other than 00:01 local time.
When you create your cache listing, set the Hidden Date with a date in the future. Example 01-Dec-2011 (assuming today is less than 01-Dec-2011).
When you are happy with your cache listing, log a Published log. You can log a Published log on the cache by clicking "Log This Cache" at the top right of the right hand navigation section. The date of the published log is NOT used to future date the cache publication. For consistency use the Hidden Date for the Published log but you can use any date you like.
At 00:01 on the AEST/AEDT Hidden Date (not your Published log) the Geocaching Australia site will publish your cache listing. So if you listed your cache with a Hidden Date of 01-Dec-2011, when the Geocaching Australia server ticks over to 00:01 on 01-Dec-2011, the cache will be automatically published.
You can find the date and time for the Geocaching Australia server at the bottom of every page on the Geocaching Australia website.