Just because he died in Return of the Jedi doesn't necessarily mean we've seen the last of Palpatine.
If you know anything about the Expanded Universe of Star Wars, then you know that the Emperor didn't quite stay dead in the books. While there have been almost no details about what the next Star Wars movies will be about, many fans have been hoping that some ideas from the E.U. will get adapted. Take it with a big grain of salt, but it sounds like they might be taking one popular plot thread to the film sequels.
According to Jedi News, Ian McDiarmid, who has been playing the Emperor for quite some time now, will be back. They report:
The specifics of the role are unclear, but it seems likely that McDiarmid will be returning to his signature role of Palpatine. Whether as the original or a clone of, we are yet to discern.
We know that the Emperor's spirit can be transferred to clones. We also know that McDiarmid has expressed interest in returning again to the role. So while this is still very much in rumor territory, it's certainly a rumor we'd like to be true.
Would you like to see the Emperor back in action on the big screen, or should J.J. Abrams' sequel focus on a new villain?
(via Comic Book Movie)