nVidia have announced the Tegra 2 replacement - Tegra 3. The chip is to contain four physical cores, and as before, high standards of graphics processing too.
This comes right after many products were launched or announced at CES in Vegas, using the soon-to-be old hat, Tegra 2 processor.
All is unknown on the release date front, but I shouldn't let it put you off the Motorola Atrix! An impending launch doesn't make the current product any worse mind, so don't be put off purchasing a Boxee Box or whatever else you had planned.
Mind you, at the rate Boxee like to delay the BBox, I wouldn't be all that surprised if they halted production, and switched back to nVidia (They previously swapped out Tegra 2 for Intel CE4100 SoC) delaying further!
Big green also stated that Tegra 4 is already in the works, and we can expect an update every year.