Difference in the 2 Batteries for G2

[BudMan]

On Canon's site they list 2 batteries as available to buy. BP-511 (supplied) and BP-512. Is there a difference between the 2?
Go to http://www.powershot.com/powershot2/G2/index.html

From here the links beside the camera don't work. I did get some to work by guessing what was wrong.
On the " An Extensive Selection of Accessories " link I did a properties on the link and changed the word in the end of the URL from "index" to "accessories". As below.
http://www.powershot.com/powershot2/G2/accessories.html# .
I did the same for the others guessing what they would say but could not get all of thm right.

[Chop_Top]

I think the only differance is the shape. One of them is flat across the side opposite the battery and the other is curved arround the batteries

[justincase]

"Behind a simple locked compartment door in the left bottom corner of the camera fits the Canon BP-511 Lithium-Ion battery pack which is rated at 7.4 V, 1100 mAh (8 Wh). It's worth noting that this is the same battery used in the EOS-D30 Digital SLR and some Canon DV camcorders (and can be purchased for approximately US$70 / £55). There will also be soon be a newer BP-512 Lithium-Ion battery, this has the exact same capacity and is only different in that it has a flat top instead of the double curved top."

from http://www.dpreview.com/reviews/canong2