It really depends on which version of WeatherBug you use.
The AWS version is legit and spyware free.
There is another version floating around that loads the spyware onto it.
www.pcpitstop.com will scan for weatherbug, and will tell you how to tell the difference between the two.
I run both Spybot S&D, and Adaware. Neither of them have a problem with the AVS weatherbug.