How do you clean your pool if the cover has been off all winter and the water is black and the whole pool has a brown slimy coatng on the walls and floor?

Any way you look at it, you have a job ahead of you. Perhaps you can gather all the potential swimmers and put them to work. [kidding] You will have to divide and conquer the cleaning project. The best thing would be to first drain, or otherwise remove, the water from the pool after raking the debris out of there. Clean the drain so it works properly. Then, rent a power washer (check with the pool company) with some recommended cleaner (TSP? Bleach/dishwasher soap?) to get most of the slime off. You may want to let the chemical sit awhile to work its magic. Finally, rinse and drain the soapy water completely. After that, you may have to still do some hand scrubbing, but it should be more manageable without the slime. Make sure you have thoroughly rinsed the pool before going in for the close work--so you don't slip or mix the wrong chemicals.