It wasn’t until today that the next installment in the Batman franchise was made official as Warner Brothers has announced a planned release date of July 20th 2012 for Batman 3. This is the exact same weekend that The Dark Knight had back in 2008.
Production on TDK started approximately 15 months before the movie ended up being released, which means Batman 3 would need to begin pre-production in early 2011 and start filming in the spring to keep a similar time frame. A script is currently being worked on by director Christopher Nolan, brother Jonathan Nolan, and David Goyer.