[1]http://src.chromium.org/viewvc/native_client/data/docs_tarba... [2]http://nativeclient.googlecode.com/svn/data/site/NaCl_SFI.pd... [3]http://naclports.googlecode.com/svn/trunk/src/experimental/v...
More about NaCl (http://code.google.com/p/nativeclient/)
Portable NaCl (PNaCl) looked very promising (targeting LLVM (bytecode) and then re-targeting your native architecture) but I haven't heard anything about it lately.