WoW: Classic is scheduled for August 27 (technically August 26 if you're in the Americas). The soonest that you can play it is starting in May, during Blizzard's scheduled stress tests. To opt-in you must have an active subscription on your Battle.net account. If you do, go to Account Management and select the Wow Classic beta. Keep in mind, there will be level caps during the test. The schedule is as follows:
Who is Joana? Joana, (AKA Mancow, or FuriousPaul) speedran 1-60 vanilla WoW from 2005 - 2007. I have been server first to level 60 seven times in a row, along with winning Blizzard's "First to level 50" contest they held back in 2006. I also have the fastest time through original vanilla 1-60 WoW in 4 days 20 hours. I have produced a very useful 1-60 horde speed leveling guide along with a 1-60 speedrun video.
With the Classic beta now out it seems every related article somehow manages to spark the eternal war of "Vanilla was the best WoW sucks now" and "lol nostalgia goggles, Vanilla sucked, enjoy your two weeks of Classic". I have to say, even though I understand the principles behind the battle and the reasons people behave and talk this way... I actually REALLY don't get it on a deeper level.
Through out the game, the quest log will be capped to 20 many times. The guide makes use of maximizing the total amount of quests you can accept at once. Because of this it is important to follow the guide exactly and only accept quests if the guide tells you to so you won't run into issues not being able to accept a quest. If you do accept a quest that is not listed in the guide, write it down because you may need to abandon it in order to keep following the guide if your quest log is full.
I received a beta invite for Classic, and had also been an alpha and beta tester for the original game 15 years ago. That isn't unique; plenty of people in Northshire Valley had had the same experience, suggesting to me that active players who were Day 1 WoW gamers or had participated in the original tests might have gotten priority invitations to this one.