IconWorkshop is a professional authoring tool that lets you produce icons for Windows Vista, earlier versions of Vista, and Mac OS X, in a wide range of sizes and formats. Novices should not be intimidated however, since IconWorkshop has an excellent tutorial available in Help and the interface is reasonably intuitive.
The program offers several different ways to create icons. For example, if you're new at icon making, you could use drag-and-drop to combine supplied elements like glossy circles, folders, and so on with a wide range of symbols, or add your own text. If you're more practiced, you could copy a graphic from Adobe Illustrator and paste it into IconWorkshop to create your icon; or you could load up a template in Adobe Photoshop and have at it. You can even open a blank icon work area and do it all freehand. Advanced editing functions include the ability to use alpha channels; brightness, hue, and saturation controls; plus rotation, drop shadow, and filters.
When you're ready to publish your icons, you have many options. You can create icons of practically any size, all the way up to 512 by 512 for Mac OS X 10.5. Formats include Windows Vista's PNG, GIF, JPEG, and many more. The program even provides a compiler that lets you distribute icon packages in compressed format.
At $50, IconWorkshop may seem a tad expensive to casual hobbyists. But for anyone who's serious about making icons, it's a great deal.