IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.
IconWorkshop - Application to create and manage software icons. A must for developers.
IconLover - Icon editor for Windows.
icoworks - .ico editor for Windows 8 and Windows RT
JDraw - Open Source SF.net
Icon Generator - Icon Generator is a little application built on AIR that lets you generate a CS5 or Web 2.