ASUS Update is a utility to update BIOS on computers with ASUS motherboards running Windows operating system. You can read this short manual on ASUS update utility published by ASUS.
At the moment ASUS Update utility reached v.7.07.07.
I have found it available for one of the motherboards, namely ASUS P5B-VM. Still, it will work for a variety of motherboards produced by ASUS.
Here are the download links.