Apple to Release new iMacs Soon?

As expected following the introduction of new MacBook models, Apple should release new iMac models as reported by Apple Insider. It should not feature big surprises but rather unify the architecture between iMac and MacBook Pro. So, we should have Centrino 2 Core 2 Duo, running on a 1066 MHz bus, coupled to DDR3 memory, and most likely to a NVidia chipset for entry level model, and a dual GPUs for the high end model, even though its current interest to save battery life time is useless on such desktop models.
It will be interesting to see how CPU frequency will evolve, will Apple maintain current clock frequency or use higher clocked model? Will the video of new iMac models be only from NVidia, or can be expect the current powerful ATI Radeon to be available too?