GW has published several new FAQ.
Namely:
Rulebook:
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1830600a_40k_Rulebook_version_1_4.pdf
generally contains only a clarification of the skimmer on large oval base.
Grey Knights:
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1830601a_Grey_Knights_v1_1.pdf
contains quite a lot of changes.
Orks:
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1490295a_Orks_Version_1_1.pdf
more or less clarification of already known facts.
Space Marines:
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1620227a_Space_Marines_Version_1_2.pdf
again, some clarification.
Cities of Death:
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1900169a_Cities_of_Death_FAQ_Version_1_0.pdf