There have been rumors that Mark Hamill, Harrison Ford, and Carrie Fisher would be returning for Episode VII. That surprises me because I'm pretty sure that Carrie Fisher didn't have a good experience with the original trilogy, and I've heard rumors that the other rumors about her aren't true. I at least hope that if Mark Hamill and Harrison Ford return, that they won't try to be in any action scenes, because this is almost 40 years since the first Star Wars movies and if they were maybe in their 20s or 30s then, then, well, you can do the math. I think we would all appreciate them appearing just as the parents of their children and not the leads in the film.
Here's a tip: don't search YouTube for any Star Wars VII trailers. They just selected the director a few months ago, and they haven't even selected the cast yet, much less started production. All the trailers will all just be either parodies, or just stitched-together scenes from other Star Wars films. Once they do release the trailer, I will post a link to it (if this blog is even still around then, because it'll be in like 3 years) but you probably won't have trouble finding it because a new Star Wars movie trailer will probably be all over YouTube very fast.