Not to sound like one of those commercials with Sally Struthers or some other celebrity advocate, but a car cannot run without gas. Without funding, the relief agencies would not be able to buy food, clothing, toys, or other essentials for homeless families. You and the government are two of the most important things to these agencies, and they depend a lot on both of you. If you see a advertisement for a relief agency, don't change the channel, write down the number. Admittedly, this will take the better part of thirty seconds to do, but I'm sure you have that time.
Food drives are also an important way of helping out the poor.
The canned food you give will help somebody get a good meal, and it might improve your conscience knowing that you've helped. All in all, there are so many ways to help, and a lot of them are so easy, you just have to care.