A utility for tuning your WiFi network? Is there an app available to help tune Wi-Fi network settings?

My local air space is starting to get congested and I want to make sure I'm using the optimal channel and settings on my router to avoid collisions and keep my WiFi as speedy as possible. I'm looking to run it on a 2010 MacBook Pro that supports up to Wireless N but I'd like to be able to tune the N and G protocols on my router (a D-Link DIR-655).
Netspot



You can use netspot to basically create a 'map' of your location, and see network information around you. It will show you areas that network connectivity may suffer. You can then revisit the data points to possibly determine better locations for your router, or where the worst offending networks are to better decide which channels to use.