It appears that we have our first two official cast members, if these other sites are to be believed. Elle Fanning and Kyle Chandler have supposedly been cast in Super 8, but there isn't really anything 100% official yet. Vulture reported this the other day and I wanted to wait a few days to see if something more official was released regarding this, but since nothing has come out either way I figured it was worthy of a post.
Elle Fanning is, of course, Dakota Fanning's sister and has been in such movies as Deja Vu with Denzel Washington and The Curious Case of Benjamin Button. If she's as talented as her sister, I think this is a pretty good casting choice and I think she'll work well.
Kyle Chandler is probably best known for his role on the TV show Friday Night Lights, but he's also been in movies like King Kong, The Kingdom and The Day the Earth Stood Still. I actually don't recall him from the movies and I don't watch Friday Night Lights, but from what you guys have said in the comments and from what I've read elsewhere, this is also another good casting choice.
So there you have it, the first casting rumors surrounding Super 8, and they appear to be pretty solid. Hopefully this is legit and official, but who knows. I would still take it all with a grain of salt until there has been an official announcement, but from my experience, Vulture is pretty good with their sources.
UPDATE: Word on the street (thanks to Singularity7) is that Kyle Chandler was seen shadowing the chief of police in Weirton this week learning the ins and outs of a day in the life of a small town cop. So if the rumors are true chances are pretty good that he's going to be playing a police officer/chief in Super 8.