I just noticed a discrepancy...
When looking under the "Tech Specs" of the new MBP (Aluminum), it shows the battery as a "50-watt-hour lithium-polymer battery". It also estimates battery life at 4.5 hours which, I assume, is the average battery length given the two video cards (9400 = 5h / 9600 = 4h).
However, when I looked up the replacement battery it shows the new MBP (Aluminum) model as taking a "60-watt-hour lithium-polymer battery".
http://store.apple.com/ca/product/MB772LL/A?cid=MKT-MACBOOKPRO
So, which is it? Are the old batteries compatible with the new?