James Cameron about the current status:
"We're very, very actively pre-producing the film right now with Universal. The design work is phenomenal, both the three-dimensional and two-dimensional design work, the physical maquettes, the CG test scenes; the artwork is phenomenal. The fans certainly won't want for a visual feast with this film. But there's [still] a bunch of number-crunching and "How you gonna do it?" and "How you gonna make it?"; "Where you gonna do it?" All that stuff."
Great article about Guillermo Del Toro with information about "At the Mountains of Madness":