About a year ago, I wrote a library called libess that loaded/parsed/saved most of the data in an oblivion ess save file (and also esp and esm files).

Now that I have Fallout 3 (and have observed how similar the data files are in both games), I intend to create a derivative of libess that will handle fallout 3 fos files (and also fallout 3 esp and esm files)

Because both games are so similar, it should be possible to reuse a fair chunk of code from libess.

Like libess, it will serve as the most comprehensive documentation of the Fallout 3 save and mod file formats out there.

First though I have to pull Fallout 3 apart and figure out how it works inside (but since its clearly a derivative of the Oblivion engine, all my knowledge of that engine should help here)

No this wont support Fallout New Vegas (since I dont own that game at this time). Oblivion is handed by libess. Skyrim is also out of the question (I dont own that game either)

The New Vegas engine is virtually identical to the one used in Fallout 3, so if you ever do get the game it will be very easy for you to port over.

Yeah I suspect as much, I just dont have the game (and dont feel like spending the $20 Steam wants for it here in my country when I haven't yet gotten bored with Fallout 3