few features have been confirmed more will be offically soon but 2 features announced will be you can now play PSP Mini games on PS3. also you can now transfer data between two systems by ethernet cable.
http://www.playstationuniversity.com/ps3-firmware-3-15-this-week-1631/
http://www.playstationuniversity.com/ps3-firmware-3-15-this-week-1631/