Microsoft® Windows® XP introduces a new style in icon design. The following guidelines walk you through the steps of designing and creating Windows XP-style icons.

The Windows XP icon style is all about fun, color, and energy?and, as there are now 32-bit versions of the icons, smooth edges. Each icon is rendered in a vector program and then manipulated in Adobe Photoshop to create a beautiful image.
More info:
hxxp://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwxp/html/winxpicons.asp