[UPDATE: Disney has notified us that they do indeed plan on bringing ALL the remaining Chronicles of Narnia movies to the big screen. According to them the source on this is completely wrong. - Vic]
We knew it was in development. But according to our buddies at Jim Hill Media, Disney and Pixar are moving forward with a film-trilogy based on Edgar Rice Burroughs' John Carter of Mars series for 2012 at the earliest... if not sooner than that.
Mark Andrews (Oscar-nominated screenwriter of Ratatouille) has already written a draft that both Disney and Pixar executives went bonkers over; crazy enough that they're seriously wanting this to become their next big franchise instead of adapting all seven Chronicles of Narnia books(!?!)
The second Narnia installment Prince Caspian will open this coming May with the third outing, and Voyage of the Dawn Treader slated for a May 2010 release.
Beyond that, there are no current plans to bring the remaining four novels to the silver screen. In fact, Dawn Treader might even be in jeopardy unless Caspian does killer box-office.
Now I can't comment on the John Carter of Mars novels since I've never read them (although I've only heard great things). But I do think placing Narnia in the summer instead of the more-reliable Christmas release is questionable... at best.
I don't doubt there is some truth to this. The further they go along with the Narnia films; they'll get more-and-more expensive. But as long as they make solid box-office numbers, Disney will continue to churn them out. This is the Mouse we're talking about here, folks!
Source: Jim Hill Media