Adding icons to firefox or thunderbird

["Eric A. Bonney" <mailinglists@vanhlebarsoftware.com>]

How do I assign the icons to firefox and/or thunderbird?  I have them 
installed an running just fine, but whenever I put an icon on my desktop 
or in a panel I get either nothing or a little gear icon for them.  I 
would like to have the normal icons showing.

Thanks,
Eric