Gconvert - GConvert icon toolkit: create, edit, extract, manage and convert icons of any size and color depth.
Icon Generator - Icon Generator is a little application built on AIR that lets you generate a CS5 or Web 2.
JDraw - Open Source SF.net
Icon Slate - Icon Slate lets you easily compose, import and export desktop icons in many formats.
IconViewer - Bot Productions's IconViewer utility allows you to view, copy, and save the icons in a file through its property sheet.
IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.