Fast Aero allows you to get aero glass effects in windows XP which is available in Windows Vista. And the best part is you just need to run it instead of installing like themes. Basically this program simulates the Windows Vista Aero effects like transparent borders, making your windows backgroud translucent, thus giving your a close look of aero effect on your Windows Xp machine.
The language set is for Polish which you can change to English when you run it for the first time. Download FastAero