I've only looked at a small sample of game saves, but from what I've seen the files appear encrypted. That may not be the case.
One mutli-platform example I've been looking at is Oblivion. Save games can be interchanged between PC and Xbox 360 with a bit of work, however games saved on a PS3 don't appear to follow the same format. It would seem unlikely that the publisher would rewrite the save routines only on the PS3 version.
I'll keep working at it, but if anyone has any further details I'd appreciate it.
Perhaps, but that wasn't my goal. I simply wanted to map out the savegame file format. There's a fairly large number of people who enjoy editing their save files for any number of reasons.