via Stickmonkey
Overview and Schedule
The Chaos Daemons release slot as last time around is a dual system release, updating the repsective armies for both Warhammer 40,000, and Warhammer Fantasy. There are a large number of models to be released as well as both books, so look for it to get broken up into 2 waves at least - with the lower possibility of 3 waves.
Look for the initial wave next month, and follow up waves a quarter later. That would put the first wave in March and the followup in June. Note however that Games Workshop has this thing for releasing Daemons in August - so that second wave might slide a little.
In any case, onto the waves themselves:
Wave 1
BloodThirster/Skarbrand (plastic)
Great Unclean One (plastic)
Chariot of Khorne/Herald of Khorne/Khorne Cannonade
(anyone remember the old epic Doom Blaster)
Plague Flies of Nurgle
Palanquin of Nurgle/KuGath upgrade/Herald of Nurgle
Fiend of Slaanesh
There is also word of a named Daemon Prince and several smaller finecast models as well.
http://www.belloflostsouls.net/2013/02/40k-rumors-chaos-daemons-pt-1.html