Quote Originally Posted by IGN
[...] As part of IGN's continuing IGN First coverage of Marvel's Avengers, we can confirm the beta dates for Marvel's Avengers:
August 7 - PlayStation preorder beta access begins
August 14 - Xbox and PC Preorder beta access begins, PlayStation open beta also begins
August 21 - Open beta across all platforms begins [...]

Crystal Dynamics will be hosting a second War Table presentation on July 29 at 10 a.m. PT to detail what players can expect out of the beta. [...]

"We built the beta in such a way that you can experience most of things that you’ll be doing in the full game,” Escayg said in a statement accompanying the announcement. “That means playing a piece of the original single-player Avengers story campaign, fighting through co-op missions, experiencing hero and world progression, and exploring War Zones and DROP ZONES, a new kind of mission we’ll talk about in the upcoming War Table on July 29. This beta is meaty, but it’s only a small part of the finished game." [...]
Marvel's Avengers Beta Dates, Second War Table Announced - IGN First - IGN