You need to open the file in a hex editor and translate the hexadecimal numbers into long floats (Or any format resembering that, it might be fixed too) and see if any of them match.
What's the format? Well that's what you are trying to find out, right? The answer is we don't exactly know. The field .a formats are availible and the battle animations are somewhat documented. Look at gears. (click on my WWW button) that will tell you what has been discovered.
The animation files are not generic. You can't put them into 3d max or something and get a bunch of bones. You have to get dirty and rip the file apart using a hex editor to find what you are looking for.
Don't know what you are looking for?
Well, none of us do. The data doesn't lay out in front of you clear as day. For example I have 248 opcodes to go through I don't know what they do. I have to use clues (Like the command AOKI, which deals with sound, I know it's sound because on yuffies menu in the debug room you ask her to kill the sound and she does. The command calls 10 AOKI commands to do it. I don't know what each command exactly does, but obvoius that all of them togeather kills the sound.
It also helps to know that AOKI is the last name of the sound programmer. He named the cammand after himself.
KAWAI is the same thing, that's the name of the animation programmer, and there are wierd calls to that comman that controld animation. I don't know what they do, but it's animation-related...