You might have read several rumours about the third and most likely final Batman film from Christopher Nolan. I won't repeat them here as it serves no point and deflates the original ideal of deliberately not posting any of them in the first place.
The short of it is that NO OFFICIAL announcement has yet been made in any regards to the next Batman film in any way. This means, plot, actors, character, themes or events. It has not even been confirmed if a script has yet been written. So before you go and read the latest of the rumours circling movie sites about "insider tips" and "overseen script notes" be aware that not a single one of them is true.
The only clear truth about the third movie is that Nolan himself said that the character of the Joker would not return as the death of Heath Ledger is still tender to him.
If you want to know you can wait until Nolan himself makes the announcement. He stated that if he was to film a third Batman he would state it before the end of 2010.