Templehof and Tegel will both be closed by 2012 to be replaced by BBI
http://www.berlin-airport.de/EN/BBI/index.html
No further room or possibility of permission to expand either of the older airports. Given the amount of private money they actually managed to raise to get BBI of the blocks I would think it commercial folly to keep either TXL or THF open. Berlin cannot support more than one airport ( currently a total of only something like ten connections a week to the US for instance) let alone 3.
Can you tell...I voted against it.