This is an excellent video overviewing what we currently know about the development of BF3. It highlights what has been confirmed versus speculated and does a great job of presenting clear and concise information.
In short, the confirmed facts are:
This will be the true sequel of BF2
It will use the frostbite engine
It will have nice environment and lighting
It will be on PC, Playstation 3 and Xbox
There will be a beta before October 12, 2011
PC version will receive special attention to ensure no “console port” feeling