I have spent some time creating various Icon sets for WWL. I have only tested these on Windows7 using the latest WWL program and they work fine.
To install, unzip into following location - (you may have to enable show hidden files and folders)
c:\users\ \ appdata\roaming\weatherwatcherlive\skins\icons
Once you have them installed, select your options for WLL and then the new Icon set you want to use. then exit, shutdown and open back up WWL and they should be showing up.