Does temperature affect the internal resistance of batteries? And does charging a "frozen" battery allow it to charge faster than a warm or room temperature battery?
Internal resistance generally increases as you lower the temperature. This is because batteries generate current using a chemical reaction and the reaction generally goes slower at lower temperatures. This article on Wikipedia claims the internal resistance of a manganese alkaline battery increases from 0.1 ohms at 40°C to about 0.9 ohms at -40°C. Car batteries, i.e. lead acid batteries, do the same as described here.
A cold battery will charge slower and will have a reduced capacity, so you want to charge at room temp if you can.