The PlayStation EU Blog has posted information for new content on November 9th, 2011. It also had a little information as to what is in store to come for Modern Warfare 3 DLC content.
Call of Duty ELITE 1-Year Premium Subscription consists of:
All the MW3 DLC (20 pieces) during the 9-month DLC season starting early 2012. Includes multiplayer and special ops maps
This means that we will see 2 new multiplayer maps and spec ops missions around twice a month.
If you have the Call of Duty ELITE service you will get all this DLC for free. Otherwise, you can possibly expect all of this DLC content to be slightly cheaper than the past.
Source: PlayStation Blog – November 9th 2011 Game Store Update