Using Windows XP Visual Styles

Using Microsoft Windows XP, you can now define the visual style or appearance of
controls and windows from simple colors to textures and shapes. You can control
each defined part of a control as well as each part of the non-client (frame and
caption) area of a window. The user can then use the Appearance tab in the
Windows Control Panel to switch between the classic visual style and other available
styles.
A visual style is included with the Windows XP release. Using helper libraries and
application programming interfaces (APIs), you can incorporate the Windows XP
visual style into your application with few code changes. For more information, see
the Platform SDK documentation in the MSDN Library.