There is a lot of Dark Angels information out there right now, including a very nice compilation of information of what is new or changed in the new codex.
Except for the disappearance of my favorite piece of wargear, the powerfield generators, Dark Angels are looking like this is an excellent update to the codex. I think the last several codices have been home runs by GW.
A Great Compilation of information, mostly gleaned from the interactive ipad edition put together by TastyTaste. Go over and check it out.
Vehicle Leaks over on Spikey Bits
Also a great compilation of leaked information on the Spikey Bits forums