Coming changes...

All of these remain under the heading 'likely to happen' until we actually see them on the field...

Planned for 2012
Carolina has introduced an updated logo and script. The logo is to appear on an altered helmet design but word from owner Jerry Richardson is that the uniforms will not change "in my lifetime."

http://www.panthers.com/news/article-2/Panthers-introduce-refined-logo/22b44075-6ab5-477d-ac6d-7d29733deea0

Denver is making their orange jersey their primary jersey which thereby relegates the navy jersey to alternate status. No changes in the designs have been announced.
http://www.milehighreport.com/2011/10/3/2466900/the-nfl-approves-orange-jerseys-for-the-2012-denver-broncos

Jacksonville will likely add a black alternate jersey that will be promoted in status in 2013.
http://www.actionnewsjax.com/content/jaguars/story/Back-in-black/Y8kNJLKlMk2KnyAGqSpqNw.cspx

Planned for 2013
2012 will be the last year for Cleveland's AL memorial on the left jersey sleeve. After 10 years, the patch will be removed for the start of the 2013 season. (Sixth paragraph from the end of the article)
http://www.clevescene.com/gyrobase/the-custodian/Content?oid=2805785&storyPage=2

Jacksonville will change to a black primary jersey for 2013, presumably demoting teal to alternate status.
http://profootballtalk.nbcsports.com/2012/02/03/jaguars-will-be-changing-to-black-uniforms-in-2013/
http://www.nfl.com/news/story/09000d5d82698ae5/article/jacksonville-to-replace-teal-uniforms-with-black-ones-in-2013