im a graphic designer what i do is either make them or you can d/l them from deviant art.com then find the icon you wish to use
go here (
http://ico.bradleygill.com/advanced.php) it will change it from a .png to a .ico image that will alow you to use as an icon you might have to shrink it down i use p/shop for that or you can use your paint program and shrink it down to 32x32