Hah! You engineers! I'm still suffering confusion because the negative pole on my car battery has a big "+" sign on it.
It's really quite simple. Here are two little mnemonic devices they taught me in graduate school:
APE = Anode Positive in Electrolysis (i.e., charging)
NAG = Negative Anode in Galvanic operation (i.e., discharging)
Of course, you must remember which is the anode and which is the cathode. The anode is the place where oxidation occurs; the cathode is where reduction occurs.
You also have to remember the oxidation and reduction half-reactions. For the conventional lead-acid battery, the half-reactions are
Pb(s) + HSO4- = PbSO4(s) + H+ + 2e-
PbO2(s) + HSO4- + 3H+ + 2e- = PbSO4(s) + 2H2O
That's all there is to it. Simply remember these simple points next time you have to jump-start your car. (Wait a second: Which pole gets the red lead, and which gets the black? I can never remember.)