A friend from online recently found out he has an extra battery for an 400D XTi that he can no longer use because he sold the camera. I have a 450D XSi and I was wondering if I could use this battery. I don't want him to send me the battery if I can't use it either, so I was wondering if they are compatible. Then I started wondering about the other Rebels, and then I started wondering in general. So,
Where can I find out what Canon batteries work in what bodies?
In particular I am wondering about these two bodies, but I am curious to know the others also.