Collider has recently sat down and interviewed Patton Oswalt, Brad Garrett, Janeane Garofalo, Lou Romano and producer Brad Lewis about Ratatouille among other things. They are very good interviews but beware, JV Pixar News points out there are WALL-E and Up spoilers in the Lou Romano and Brad Lewis interviews. Nothing too drastic, but still, some people way not want to know.
Collider Interviews Ratatouille Cast

its nice to know these things
but what do u honestly think about 1/3rd of the film (wall-e) being silent
it looks like an obvious blockbuster
it appeals to everyone a CUTE (appealing to young girls) ROBOT in SPACE (appealing to young boys).
and dont u all want to know more about up
i guess it has a good story
becuase it’s captivating me already
i just hope its extra appealing because i know kids wont want to see just an old man
but theres a young wilderness ranger so that fixes it
and a sure-fire way of making it a blockbuster
casting someone young and famous as the wilderness ranger
and a middle aged comedian (with an old man voice) as the senior
I really appreciate you warning us of spoilers. I’ve already seen Ratatouille (you’ll love it), but still, for Wall-e and other upcoming Pixar movies, I want to stay away from a lot of the “inside-info” that I find myself gorging on too much!