The GTX 660 Ti specs have managed to leak out and they are quite promising. The GTX 660 will be based on the same core as the GTX 670, which is the 28nm GK104 GPU. In addition, the GTX 660 Ti will have 1344 CUDA cores and 2GB of GDDR5 memory, which is the same amount as the GTX 670. In fact even the core and memory clocks are supposed to be the same as well ( 915 MHz core clock and 6008 MHz memory clock). So, what makes the GTX 660 different? The GTX 660 will have a 192-bit interface as opposed to a 256-bit interface, which is around 25% less memory bandwidth in comparison to the GTX 670.
So, the GTX 660 Ti is going to be quite a card and it is expected to be released August 16th, the first day of GamesCom. Interestingly enough Nvidia claims their wont be any shortages and this will be a hard launch. However, the price of this new card from Nvidia is unknown at this point in time.