I put in the shared memory into 98.15nitsuja (although the version number is wrong in the program; I'll look how to fix that later). Let me know if you find any bugs. It wasn't much more than a bunch of cut and pasting. (I also used better programming practice, and #ifdef'd all the memory sharing code, so shared memory can be disabled when compiling.)
http://lukeg.50webs.com/fceu-sm.exe.hah
delete the "hah" at the end (50webs wouldn't let me upload an .exe lol)
Ok now I have a question for you (or anyone who knows about this): Can you write to the shared memory? I'd assume yes, unless that privelege is reserved for FCEU? If you can write to the shared memory, that would be an easy way to send messages to FCEU, and then custom-made bots would be nice to make :) The code for allocating the memory is:
mapRAM = CreateFileMapping((HANDLE)0xFFFFFFFF, NULL, PAGE_READWRITE, 0, 0x800,"fceu.RAM");
RAM = (uint8 *)MapViewOfFile(mapRAM, FILE_MAP_WRITE, 0, 0, 0);