They are both completely different formats, their save files are unique to each system and cannot be read by one another, unlike word or excel document's etc that can be read by different programs across multiple formats Iroinically, the saves may very well contain the exact same data (for cross platform games at least). It's hard to say without breaking out a hex editor, but I don't see why the devs would re-write the save system for what is essentially a high level I/O task. Both consoles write some sort of user ID into the save files - the 360's is 25 digits long IIRC - making the chances of the ps3 giving you the same ID to be 1 in 1,000,000,000,000,000,000,000,000 - and that doesn't take into account different formats that the ID is saved in. Then you've also got the Device ID that the save was originally made on to prevent sharing.
Oh ok, I was wondering this because I found a save file for the Void Star achievement that I'm currently working on, but it was for PS3 and it would make my life a hell of lot easier if I was able to convert that save to 360 but I guess its not possible.
