According to a StarCraft 2 forum MVP on the Diablo III forum of the BlizzCon forums, the Beta will "go live" by September 30th. It isn't exactly clear what "go live" means, but it probably means an open beta since internal beta testing is likely already going on. The MVP appears to be taking part in playtesting at a press event happening around now, but with embargoed info. Official info about the beta will probably be out before the weekend, if this semi-leak is correct.
- ↑ Sixen (7/25/11 4:39 PM). "#7 - Diablo 3 Beta". BlizzCon - Diablo III forum. “Supposedly, the Beta will go live by September 30th, as long as there are no major delays. I'm going to BlizzHQ on Wednesday to playtest the Beta, as part of a press event as well... I think we're almost there.
If all goes well within the Beta, it's very possible to have a 2011 release.”
Note: Since this was on Blizzard's forums, they could delete the thread. FYI.