No word yet. You may want to keep an eye on the Toy Biz LotR site for any updates.
No doubt there'll be a Denethor figure, though. Perhaps a few new Orcs, new versions of the Fellowship, a nicer looking Faramir (here's hoping!), and some impressive horse & rider sets (hopefully including Theoden and Snowmane this time). That's just my own speculation, but I wouldn't be surprised since that's how it went with TTT.