How to test wifi?

grilled-cheese writes: I'm working for a growing university's IT department and we are growing more and more concerned with our wireless network. While we have managed to feel pretty good about our security solution, we don't have a good method for planning, analyzing, and troubleshooting our existing infrastructure as it grows. How would you go about troubleshooting your wifi problems, or surveying the current setup? Is there a published standard for wifi coverage or utilization? What would be some important factors in your wifi planning such as Signal-Noise-Ratio and Multipath?