How many hours till the first part of the World can try for stamps?

Did they say it will be available on March 30th？
Well it's 5pm in Australia, and still nothing.

I think they will flip the switch for everyone at the same time, so that means that if they do it at the normal time we will see "Quests" in about 9-10 hours.

Hopefully sooner than that, but Niantic doesn't usually change the time for when things start.