Beamdog have a digital magazine now and it's free (~quarterly release). It's called
The Familiar (their should be a web version ~next week according to Amber Scott in the forums).
The first issue contains a short story about a new companion in Siege of Dragonspear, more information on Beamdog and other stuff. The second issue will be in late March..for secret reasons (I'll guess Siege of Dragonspear release).
I'm off to read it, I'll update the post if there is some more Siege of Dragonspear info.
edit
I learned something: Baldur's Gate city ground was a photograph of coffee beans. lol. There is a nice image per image showing how they improved that for Siege of Dragonspear.
There is a bunch of concept arts vs final look for zones in SoD too. They also talk about the technical changes they had to do to improve the UI.
There is stuff about cRPG renaissance which include "interviews" with Dan Tudge (N-Space/Sword Coast Legend), Feargus (Obsidian/Pillars of Eternity) and Swen (Larian/Divinity Original Sin) and the Beamdog guys of course.