Battlefield 3 beta will begin at somepoint in September. Daniel Matros, Global Battlefield Community Manager at DICE on his personal Twitter account clarifies some important details related to the upcoming Battlefield 3 beta.
A fan asked Daniel, "What do you mean by an open beta. Will it be open for everyone"?
To this Daniel replied: "As we said at E3. Open for everyone"
Regarding the beta access for buyers of Medal of Honor Limited Edition, Daniel said:
"Hey! The beta for MOH buyers hasn't been announced yet."
It seems like MOH Limited Edition buyers will get an early access or there will be a separate beta for them. However details are yet to be announced.
Source: http://www.gamepur.com/news/4622-dice-battlefield-3-beta-moh-buyers-not-yet-announced.html