I believe if you read through the cycling article it proves what I'm trying to say.
http://www.aquariacentral.com/forums/showthread.php?t=64301
"A second type of bacteria establishes itself to consume NitrIte it then produces waste in the form of Nitrate.
Nitrate by comparison to the first two is benign. Long-term exposure to high nitrate levels is hazardous to your fish’s health, but typical, reasonable levels of Nitrate are not harmful. Nitrate must be removed either via water changes or plant consumption. In most cases water changes are the solution, in planted tanks nitrate is consumed, but water changes are still typically needed to balance fertilizers and reduce other pollutants we cannot test for. So in a nutshell Water changes are almost always needed to keep you tank clean and healthy. Most people who understand the process well target something between 20-40 ppm nitrate in their tanks. They establish a maintenance and feeding routine that keeps the levels where they want them, and keeps their fish healthy long term. There are occasional reasons to keep nitrates much lower, and vice versa, some of these will be covered later in the article so please read on."
"As far as cycling, nitrates indicate the completion of the second stage, so a nitrate test helps in ensuring the cycle is done. Without knowing we have nitrates we cannot be 100% sure we finished our cycle."
This is quoted straight from daveedka, who wrote the article on cycling.
There is other info on nitrates as well, but I guess I'm being lazy, don't feel like quoting it all. I would really encourage you to read through the cycling article though, both for your benefit and the benefit of your fish.
Can anyone else back me up on this please??