Besides the bump in frequency, Intel is also adding two new features: the Atom N570 is the first low-power Atom processor to support virtualization and the amount of RAM supported has doubled from 2GB to 4GB. Interestingly enough, though, it looks like the new chip might not support Hyper-Threading. While the Atom N550 has 2 cores and 4 threads listed, Intel's N570 product page says the chip has 2 core and 2 threads.
The Intel N570 processor is already shipping in Acer Aspire One AOD255E and HP Mini 110 netbooks, and will arrive in other systems from Asus, Samsung and Lenovo later this month. It can also be found on SeaMicro's newest ultra-dense, ultra-low power Atom-based server solution, the SM10000-64, which holds as many as 256 Atom N570 processors.