Imagination Technologies who make graphics chips and bought the chip designs of MIPS have made the underlying MIPS processor design available to academic institutions for free. 
The CPU has all the features (MMU, cache controllers, debug interfaces, etc.) that a modern operating system needs to run (such as Linux and Android). The actual RTL is included in the release.
This will allow the running of the CPU on an FPGA (field programmable gate array) and Imagination Technology hope that it will lead new new innovations in the Internet of Things, mobile and automative arenas.
This is the first time a complete commercial CPU has been released and is pretty innovative of Imagination. There is a site Opencores and someone did post an ARM compatible CPU, but it was pulled at the request of ARM.
