That's right, DICE has confirmed that they are hard at work on Battlefield 4 and preparing for the Beta phase which will likely come some time in 2013. There's really not a whole lot to add as DICE are kind of keeping things under wraps at the moment and instead state that they "...hope you will continue to enjoy Battlefield 3 and all the Battlefield 3 Premium content still to come." However, if you pre-order Medal of Hono(u)r Warfighter you are apparently guaranteed access to the Battlefield 4 beta when it is available.
If I am 100% honest it seems a little too soon after Battlefield 3 to start talking about Battlefield 4 but that's just my opinion. I'm also slightly discouraged that EA/DICE is going down the route of offering beta access as an incentive to order other game titles. It's a trend that seems to have started with Blizzard's WoW Annual Pass and the Mists of Pandaria beta access, and I'm becoming a little bit concerned that it it is becoming more and more prevalent as a marketing tool and essentially constitutes 'early access' to a game rather than as a genuine means to beta test games to evolve and improve them. Although that's a topic for another day.