With VistaMizer you trim the interface of Windows XP and 2003 to Windows Vista.
For this round about 400 system files with new images and symbols will be modified. Desktop, Taskbar and Start Menu shows up for you also in the new look. The optic also spiced up with new fonts.
Is this not enough for you, you can install the ExpansionPack. This will install some 3. party applications, which rounds up the transformation.