Oh goodie. Zepy reports:

Azuma Kiyohiko will be doing three all new chapters for the new monthly magazine by Shogakukan called Gessan (short for Monthly Shounen Sunday). These new chapters will also be in the Shogakukan special re-release version of Azumanga which will be recompiled to 3 books instead of 4.

On Mr. Azuma's own blog, I can only see the mention of republication, but nothing about any new chapters.

Dear Azuma-sensei: you know how much I hate milking and how much I love Azumanga. Quit these enabling violations already, for my sanity. Also, if you keep it up, an OVA cannot be far behind.