I thought I'd explain what a system looks like and at the same time experiment with this blog's image capabilities. I have some images over at Flickr and I'm going to try to embed one of them. So here's the image of an NFT (Nutrient Film Technique) system I built a few years ago. I did it to experiment with growing leafy crops like lettuce. Up until then I'd only done tomatoes.
So here's the example. It's shown while it was being built. The frame is just PVC with flat channels. The trash cans (one of them) will be used as a nutrient tank (water + nutrients) with a pump in it which pump the nutrient to the ends of the channels. You can see the main feed tube (black) that feeds a PVC pipe and each of the channels if fed by a little 1/4 inch tube from the PVC pipe. The nutrient rums through the channels by gravity and is collected by the return and runs back into the tank. This little circulation goes on all the time.
As long as the electricity holds out and you don't let the tank go dry (plants use a lot of nutrient and water as they grow) that's the whole deal except for a few picky details like making sure that the nutrient is at the right strength to feed the plants. Simple and fun! Also pretty trouble free.