MetaGeek Wi-Spy 2.4 GHz Spectrum Analyzer
http://www.metageek.net/index.php
http://www.thetechlounge.com/article/282-1/MetaGeek+WiSpy+24+GHz+Spectrum+Analyzer/
Do you have a wireless network? Do you have a cordless phone? Do you own a microwave? Most likely your answer to these questions is yes, which means you probably have interference. The issue at hand is not whether you have interference, but whether its effects are felt. Although most wireless boxes are able to push through the lower amounts of interference, some people, such as those living in apartments or otherwise deluged with many wireless signals may have problems. It is with this dilemma in mind that the people at MetaGeek created the Wi-Spy spectrum analyzer