[Techtalk] Icon editor

[Dan Richter]

I've noticed that Mozilla supports supports a [LINK REL="shortcut icon"] 
feature which is becomming more popular on web sites (especially the 
open-source savvy sites). This file inevitably ends in .ico, suggesting 
that it is the kind used on Windows.

Can anyone suggest an image editor that can write icon files? Note: I'm 
sure someone is going to say "Gimp", but in that case please give me 
specific instructions on converting from some other format to icon, because 
I'm not familiar with the Gimp.