For my Eberron AoW campaign, one of the simplist things to do is use the Day of Morning as the first "herald" of the Age of Worms. Other than that, travel and organizations really make the Eberron "feel" for me, so I am moving the adventures all over the place.
TRAVEL:
WC & TFoE (and GoW) are set near Silver Lake, which sits on the border of Breland, Aundair, The Eldeen Reaches, and Droamm.
EoBK is in Qbarra (Duh) and shows how the problem is global already.
HoHR (which needs major overhaul for Eberron) and TCB are set in Sharn, where all of those Changelings (not Doplegangers, save for Ixiaxian and Telakin) are a splinter group of the Tyrants, and Zyrzog has a loyal following of Dolgaunt Monks instead of the misplaced Drow. I thought about making Zyrzog a Rakshasa and spilling the Lords of Dusts involvement (and I still might) but for the moment I like the "oh god, the Daelkyr are rising" misdirection.
For later adventures I haven't decided yet, but Kyuss's city he necro'fied will be either on Xen'drik or Sarlona, the Rift in the Demon Wastes (maybe Droamm, others) and other possible fantastic places as dictated by the later adventures.
ORGANIZATIONS:
The Chamber is clearly involved, on both sides of the conflict. Dragotha worked to free Kyuss the first time, and was rewarded with Dracolich'dom for her efforts, and the dragons under her (Ithane the Black, others) are rallying to her interpretation of the Draconic Prophecy. For the good guys we have Manzorian, an aged archmage who is actually an agent of the Chamber and dragon in disguise. Manzorian, too, knows that the Age of Worms is coming, and has uncovered a bit of the Prophecy hinting at how it could be stopped. Manzorian uses mortal agents (Alustan, Eligos, others) to ferret out more information and drive the prophesized heroes (the PC's) toward their goal.
Other than that, the Dragonmarked Houses, religions and governments of Khorvaire, Arenal, and Sarlona would be most interested in what's going on. Encounters with the Emerald Claw, Dreaming Dark, Shadowmarked houses, and other nefarious and sneaky groups should be frequent once the PC's have left Diamond Lake to add flavor to the setting but not detract from the overall plot. The Dreaming Dark would be interested in why the ruins of Kyuss's city are starting to become active again, the Emerald Claw persuing rumors of "unkillable zombies", the Shadowmarked houses working to find out what the Ebon Triad is doing (so they can sell the info) etc.
And always remember, the Lords of Dust have been working for a long time to bring this to fruition. They should have their backwards fingers in just about every slice of the pie, and deal with threats to their plans swiftly and harshly.
All for now...
-Ryn