On Monday Intel announced the Xeon Phi co-processors, which is what was codenamed Knights Corner. Xeon Phi is meant to take on highly-parallel applications by effectively providing a supercomputer on a chip. The first Xeon Phi product will provide one TeraFLOP of performance while occupying a single PCI Express x16 slot.
The Intel Xeon Phi will begin shipping later this year but pricing information has yet to be published.
More information on Knights Corner / Xeon Phi is available from this Intel blog post.
Earlier this month Intel published the open-source Knights Corner Linux code. The Intel co-processors for massively parallel computing will be backed by fully open-source support with modifications to GCC, the Linux kernel, GDB, etc.