Yes its been announced and Charles promised "more details in the near future".

but the phase 'compiling in the cloud' was very confusing, people thought Microsoft just run NGEN on the server and call it a big feature of innovation, that will be lame.

I think 'optimizing' is more appropriate here. Actually Kevin Gallo said apps will 'start faster and run faster', while NGEN or pre-jit might help in startup performance but can do little about runtime performance, so I think this 'Cloud JIT' or 'Cloud Code Generation' thing should be more like optimizing AOT compiler for MSIL, in order to improve the overall performance of managed apps.