The following message was posted to the fan site:
Thanks to Eva's management, I can now officially say that Eva has no interest or involvement whatsoever in Justice League of America. She has no films to announce as yet. There's no official word yet on whether New Line will proceed with the next Dark Materials film, but they think they'd shoot the 2nd and 3rd film together if they go for it.
And in case you missed December 14th 2007's post, she isn't involved in Twilight either.
Justice League of America brings DC Comic's greatest heroes together for the first time on the big screen. Superman, Batman, the Flash, Wonder Woman, Green Lantern and the Martian Manhunter will all band together to save the Earth. Justice League of America is scheduled for a 2010 release.