CandyBar is quite simply the easiest, quickest and by far, the safest way to customize the icons found in the system and application toolbars of Mac OS X. But CandyBar doesn't stop there, oh no. CandyBar also lets you customize apps, folders, clipping icons, locations and even the OS X Trash icon!
Desktop Manager 0.5.2rc2 beta
Richard Wareham, http://wsmanager.sourceforge.net
Requirements: Mac OS X 10.3
Desktop Manager is the developer’s pet project to implement an easy-to-use virtual desktop manager for OS X. Note: This software is alpha quality. Use at you rown risk. It has only been tested with Mac OS X version 10.3 (Panther). On other versions your milage may vary.
Requirements: G3 or faster Mac, Mac OS X 10.2.1 or later
Spunk up your interface with custom icons. This app provides an easy way to create custom folder and file icons instead of using the old John Doe and Plain Jane ones. It supports drag-and-drop, features picture-to-icon creation, live icon resize, and more. Icons can be viewed in OS X or Classic.