Jack up each wheel, 1 at a time and remove the wheel. Get an assistant to operate the handbrake and watch the cable where it attaches to the rear brake on each side to ensure that the cable goes tight and slack as the hanbrake is pulled and released. Assuming the cable is operating normally, try this next. If brake shoes are fitted hit the centre of the drum the wheel bolts onto around the edge with a club hammer. If discs are fitted hit the brake calliper but be careful not to damage the bleed screw. Do this on both sides and if the brakes are siezed due to rust binding pad to disc or brakeshoe to drum, it will free them. This problem is very common where vehicles have been standing for long periods and in very cold weather when the handbrake is left on. Simply leave the vehicle in gear with handbrake off in these circumstances. Before trying anything at all you could simply start the car and use 1st and reverse gear backwards and forwards to try a quick release but be careful not to overdo it or you might burn your clutch out.
John, December 2007