We've done some homework here and most people agree that it does help hold the charge to a certain extent, but it's not very practical since the increase is near negligible. When you freeze/cool batteries, you cool down the particles inside, making them react slower, and are less prone to loss in charge. This is all in theory, but because it's slowed down, the current is released slower, decreasing output/power of output.
Then again, we're not certified Mythbusters either. We'll let you guys tackle this one!