My favorite cold remedy is hot lemonade. Boil one cup of water, add the juice of one fresh lemon, a tablespoon of honey and a dash of cayenne pepper. Honey is anti-viral and anti-bacterial and the cayenne pepper heats up your body, which, according to Chinese Medicine, will help burn out the cold germs.
I use this every time I get a cold. Altho I think the real key is to boost your immune system so you don't get colds in the first place.